getview vol 4 no 4 july 2014

Committee of the Global Engineers & Technologists Review

Chief Editor Ahmad Mujahid Ahmad Zaidi, MALAYSIA

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Mohd Zulkifli Ibrahim, MALAYSIA

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ZIMBABWE

Dear the Seeker of Truth and Knowledge

“Everything is now available on-line” First, over the past two decades of the way how scientific journals are published and disseminated has been a marked shift from the print versions of most journals to e-journal forms. Second, by the increasing competition for the publication of scientific research that has led to an increased emphasis on determining the perceived "quality" or "status" of a specific journal, then scientists want to publish papers in journals, especially in where their work is likely to have the highest impact. Third, many academic works are unnecessarily dense with respect to the writing style. Even though, it is worth noting that there are critics of the many-eyes concept. Sometimes this is unavoidable due to the prerequisite knowledge needed to grasp the underlying meaning of an article. Considering on above reasons, journals like GETview are certainly only want to publish original research that will have a significant impact and therefore it is necessary to explain how your paper differs from previous work, why your paper is important, and what new insights it presents. Since the GETview is also an online initiative designed to provide a platform for the disciplines of the engineering and technology sciences - where students and professionals alike can engage in provoking and engaging explorations of knowledge that push the boundaries of disciplinary lines - by such opening space for cross-disciplinary discussions are, hopefully, it could inspires an intersectional investigation and consideration of the most compelling issues in our changing world now. Hence, in an ongoing effort to acquaint our readers with the prominent scholars making up the editorial board that advises and serves the GETview, we are honored to provide the independent's evidence-based and authoritative information also the advice concerning engineering, technology, and science to policy makers, professionals, leaders in every sector of society, and the public at large. Certainly, involving yours; with the interest and expertise, through paper submitted and published in the GETview. Prof. Ahmad Mujahid Ahmad Zaidi, PhD. Chief Editor The Global Engineers and Technologists Review

©PUBLISHED 2014

Global Engineers and Technologists Review

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ISSN: 2231-9700 (ONLINE)

Volume 4 Number 4

July 2014

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Vol.4, No.4, 2014

1. EDGEWISE COMPRESSION ANALYSIS OF SANDWICH STRUCTURES MADE FROM CHOPPED STRAND MAT COCONUT FIBER FILLED POLYURETHANE FOAM AS A CORE MATERIAL JENNISE, T.T.T., HAERYIP SIHOMBING and YUHAZRI, M.Y.

8. FEASIBILITY STUDY OF RUBCRETE COMPOSITE USING USED SHREDDED

RUBBER: EVALUATION OF COMPRESSIVE STRENGTH AS PER ISO 1920-4:2005 STANDARD UMAR NIRMAL, JAMIL HASHIM and SANJEEV KUMAR

© 2014 GETview Limited. All right reserved

CONTENTS

ISSN 2231-9700 (online)

GLOBAL ENGINEERS & TECHNOLOGISTS REVIEW

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G.L.O.B.A.L E.N.G.I.N.E.E.R.S. .& .-.T.E.C.H.N.O.L.O.G.I.S.T.S R.E.V.I.E.W

1

JENNISE1, T.T.T., HAERYIP SIHOMBING2 and YUHAZRI3, M.Y.

1, 2, 3 Faculty of Manufacturing Engineering

Universiti Teknikal Malaysia Melaka

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MALAYSIA [email protected]

[email protected] [email protected]

1.0 INTRODUCTION In the 21st century technology era, there is almost everything can be produced synthetically including hybrid sandwich structure. Wang et al., (2012) and Menezes et al., (2012) suggested that synthetic means artificial, made by combining two or more chemical substances rather than being produced naturally by plants or animals. The cost for the sandwich structure either in terms of manufacturing cost or the selling price is somehow very high (Eekhout, 2010) and (Park et al., 2009). It is because the hybrid sandwich structure involves a pretty expensive fabrication technique. According to Okada et al., (2009) supported by Vinson and Sierakowski (2008), the current process for fabricating hybrid sandwich is expensive and complex which require special equipment and machine. What makes the situation worse is the sandwich is not fabricated using the natural green material but synthetic material instead. Another sum of amount goes to the preparation of the synthetically produced raw materials. Sandwich structure is made of skins of higher performance materials sandwiching a low density core at the middle (Lefebvre et al., 2008). According to Ashby et al., (2007), making sandwich composites by incorporating foam as its core will extend the range of stiffness and strength. Some foam is manufactured by trapping bubbles in a melt and solidifying the troth as a slab. The prediction of the composite properties is expected to fall between those of matrix and filler, following the law of mixtures type formula which is supported by Tognana et al., (2009) and Ku et al., (2011). From the viewpoint of Thomas et al., (2012) and Pandya et al., (2011), hybrid composites usually refer to composites containing more than one type of filler and or more than one type of matrix. Hybrid material is a combination of materials from different classes such as synthetic and natural raw materials together to produce a new material. One of the raw materials could just be air as to produce the foam core. Hybrids allow innovative design solutions and improvements in performance, exploiting the individual properties of the component materials. They are commonly used for improving the properties and lowering the costs of conventional composites. Regarding the classification of hybrids, one of the conditions is that the length scales of hybrids are mostly relatively coarse fibers between 1 to 10 µm and the layers of laminates and sandwich panels are between 0.1 to 10 mm (Lebée and Sab, 2012), (Rhymer et al., 2012) and (Kim and Lee, 2012). By combining natural green and synthetic raw materials, a hybrid novel material of sandwich composite can be produced which draws on the advantages of both the materials. Together these materials hold potential

ABSTRACT

Natural fiber composites have been demonstrated to be an effective and economical composite material in place of composites made up of synthetic fibers. Biodegradability, renewability and ecologically beneficial to the environment are factors encouraging the natural fiber composites to be a potential green material. The natural fibers such as coconut, banana, hemp and jute are utilized into composites as reinforcements in plastics and the need is increasing drastically. In this research, the application of coconut fibers in the sandwich core reduces the amount of polyurethane needed for the fabrication of sandwich structures made from chopped strand mat coconut fiber filled with polyurethane foam which directly decreases the cost involved and its density. A comprehensive study regarding the edgewise compression is investigated to further understand its properties and failure behaviour. Keywords: Flatwise Compression, Chopped Strand Mat, Coconut Fiber, Polyurethane Foam. Article History: Received 15 March 2014, Accepted 17 June 2014.

EDGEWISE COMPRESSION ANALYSIS OF SANDWICH STRUCTURES MADE FROM CHOPPED STRAND MAT COCONUT FIBER FILLED POLYURETHANE FOAM AS A CORE MATERIAL

Global Engineers & Technologists Review, Vol.4 No.4 (2014)

© 2014 GETview Limited. All rights reserved

2

for building a novel structure which has superior properties than in their individual states (Reany, 2009). From the opinion of Robert (2006) and Leong et al., (2003), hybridization effect would help to enhance the resistance of the composite to severe environmental degradation. The idea of using green material in place of synthetic material for the core in sandwich structure is to promote the effort of utilizing the natural product at the same time reducing the waste material production. Besides, it reduces the dependency on the synthetic material by adding values to the waste product. In this way, at least the material cost or the process cost can be lowered to certain extent at the same time to generate an environmentally friendly material. In this research, a study was conducted to investigate the mechanical performance properties of sandwich structures made from chopped strand mat coconut fiber filled with polyurethane foam under edgewise compression test. The different number of glass fiber layer applied as its skin would definitely affect its mechanical properties as well as physical properties. Therefore, it was important to find out the sandwich structure which could mechanically and physically perform to the optimum conditions.

2.0 MATERIALS AND METHODS The behavior and performance of any specimen materials was fully dependent on the material selection. The selection of raw materials was mainly based on the properties of the materials that were suitable and needed for the product application. Besides, there were also other factors that had to be considered such as the economical and safety factors that influenced the choice of the raw materials used. In this research, the materials used were roving woven glass fiber type E (600 g/m2), chopped strand mat (CSM) coconut fiber (about 2 inches in 2D random pattern), unsaturated polyurethane (petroleum based, A & B) and general purpose polyester resin as shown in Figure 1.

Figure 1: Raw materials (a) CSM coconut fiber, (b) E glass fiber, (c) Polyurethane, (d) Polyester resin.

A piece of chopped strand mat coconut fiber was placed onto a wooden mould sized 500 mm (L) X 500 mm (W) X 8.3 mm (H) that had been applied with gel coat. In the experimental work, the liquid polyurethane was mixed manually between polyisocyanate and polyhydroxyl which highlighted by Erik (2010) at the ratio of 1:1. The polyurethane was poured quickly onto the centre region of coconut fiber as it would start to expand. The mould was covered to allow the chopped strand mat coconut fiber filled with polyurethane to expand to the height of the mould. The mould was placed under the hydraulic press machine at pressure 1 tonne for an hour at room temperature. They foam core was taken out from the mould and excess polyurethane at its sides were

(a) (b)

(c) (d)



3

removed. Figure 2 shows the complete cycle to produce a panel of CSM coconut fiber filled with polyurethane foam.

Figure 2: CSM coconut fiber filled with Polyurethane foam (a) CSM coconut fiber in mould, (b) pouring the polyurethane, (c) the polyurethane-coconut foam core remove from mould, (d) close-up.

The number of ply for glass fiber to be laminated is according to the serial number such as zero to four plies symmetrically with the polyurethane coconut fiber foam core at the centre of the sandwich. Test sample SN 1 made up solely core that consisted of chopped strand mat coconut fiber filled with polyurethane foam. This foam core structure applied in all the samples. SN 2 until SN 5 each had glass fiber sandwiching the core with SN 2 consisted of a ply of glass fiber. This combination increased a ply of glass fiber for each serial number with SN 5 had a total of four plies of glass fiber as shown in Table 1.

Table 1: Coding of samples and their formulation based on layers, orientation and arrangement in the sandwich composite structure. Serial Number Layer Sequence Designations SN 1 PCF [RPCF] SN 2 G / PCF / G [0G / RPCF]s SN 3 G / G / PCF / G / G [0G

2 / RPCF]s SN 4 G / G / G / PCF / G / G / G [0G

3 / RPCF]s SN 5 G / G / G / G / PCF / G / G / G / G [0G

4 / RPCF]s Note: PCF is polyurethane-coconut foam core, G is glass fiber, R is random (not represent the angle of orientation).

Several pieces of glass fiber type E with the grade of 600 g/m2 were prepared into the dimension of 500 cm2. The amount of polyester used as resin was highly dependent on the weight of glass fiber at the resin/reinforcement ratio of 1:1. The polyester was added with 1 to 3 % of Methyl Ethyl Ketone Peroxide (MEKP) hardener and applied evenly onto the glass fiber via hand lay-up technique in a constant direction on a glass mould that coated with get coat. The sample was left for room temperature curing for 24 hours and dried under ¼ tonne pressure. Figure 3(a) shows the five specimens from each serial number were prepared into the dimension of 25 mm2 according to ASTM C 365-11, meanwhile Figure 3(b) shows specimen under the test via Universal Tensile Machine (Shimadzu) at cross speed of 5.0 mm/min.

(a) (b)

(c) (d)



4

Figure 3: The specimens (a) the specimens before test, (b) under the test.

3.0 RESULTS AND DISCUSSION According to Di Bella et al., (2012) and Erian (2004), the edgewise compression test was carried out to differentiate from the flatwise compressive test because the delamination between fiber and core was more effective in edgewise compression. The test performed to evaluate the effect of impact damage on the mechanical respond of the composite sandwich structure. Edgewise compressive tests were performed to find the difference in strength of the sandwich panel when compressive loading is applied in in-plane direction. The purpose of the test was to investigate the difference in strength with respect to core thickness of the sandwich panels and to predict the expected failure mode a sandwich panel could suffer in this kind of compressive loading. Figure 3(b) reveals the defect appeared on the specimen during the edgewise compression testing. The most common and dangerous defect is the facesheet/core interfacial debonding. In general, this kind of defects may lead to the significant strength reduction under compressive loading. With the increasing of loading, defects may propagate and ultimately precipitate the catastrophic failure of the entire sandwich structure. Edgewise compressive force is the compressive force exerted on the sandwich composite structure from the sideways of the specimen to test how strongly the facesheet is bonded to the foam core. Figure 4 shows the edgewise compression force trend. From the result showed in Figure 4, the compression force increased from SN 2 to SN 5 with SN 2 as the lowest which was 1020.31 N. It increased 114.95 % to 2193.16 N for SN 3. Again, the force further increased to 4406.53 N and 4889.47 N for SN 4 and SN 5 with a growth of 100.92 % and 10.96 %. Samples from SN 1 were not used for edgewise compressive testing as the specimen only consist foam core without glass fiber (meant that SN 1 is not sandwich structure). It is because the compressive force was coming from the direction parallel to the sandwich facing plane to determine whether there was delamination occurs in between sandwich core and the skin region.

Figure 4: Edgewise compression force.

SN 5 showed the highest edgewise compressive force in assessment with other specimens. However, edgewise compressive force for SN 5 should be even much higher in view with the significant increase of edgewise compressive force SN 2 until SN 5 with the increase of skin thickness. It was because sandwich panels

(a) (b)



5

in this mode of loading commonly fails by facing wrinkling (dimpling), shear crimping or overall buckling. Therefore, it was rare to obtain the ultimate compressive force of the facing material, but results gave a nearer value of compressive strength that was still higher compared to its previous specimens (Kha, 2006). Facesheet debonding and wrinkling failure modes were often the cause of low energy absorption in composite sandwich panels under edgewise compression loading as claimed by Jeyakrishnan et al., (2013), Butukuri et al., (2012), Scott and Daniel (2011), and Sezgin et al., (2010). Facing compressive stress is the compressive stress coming from the direction of top and bottom of the sandwich composite. Based on the result showed in Figure 5, facing compression stress was increasing gradually for sandwich composite with different number of skin layer of SN 2 to SN 5 respectively show a reading of 185 MPa, 3.31 MPa, 6.02 MPa and 7.05 MPa with an increase of 78.92 %, 81.87 % and 17.11 % respectively when comparing to the previous specimen. Facing compressive stress graph was developed from the edgewise compressive force graph. As a result, the pattern of both the graphs was very alike and highly related to each other. In this case, the facing compressive stress was the ultimate load per area of both facings. If the facing was not properly bonded to the sandwich core due to fabrication, the ultimate load could be decrease thus causing the facing compressive stress to decrease as well (Menta et al., 2012) and (Kha, 2006).

Figure 5: Edgewise facing compressive stress.

Figure 6(a) shows the delamination between core and skin. Sample from SN 2 had revealed a clear delamination between the core and skin. The defect can clearly be spotted using naked eyes and under digital microscope. When edgewise compression was applied to the sample, defect was found on the sample as it absorbed a significant amount of energy. The fiber glass skin was still partly attached to the sample. Figure 6(b) shows one side with delamination and another side without delamination Another phenomena is shown in the sample from SN 4 which is 1 side of the glass fiber skin has shown delamination while the other side is still attached to the sample. This could be due to the sample was not parallel to the direction where load was applied. Therefore, uneven load was exerted on one side of the glass fiber skin. As a result, it caused the fiber to withstand more edgewise compression than the other

Figure 6: Defect and specimen components (a) 200x magnification, (b) 50x magnification.

(a)

Glass fiber

Delamination

PU foam

Coconut fiber

(b)

Delamination between core

& skin

No delamination between core &

skin



6

4.0 CONCLUSION The edgewise compressive properties are increased uniformly as the thickness of the sandwich increased. From the results and discussion concluded that the chopped strand mat coconut fiber filled with polyurethane foam is the best as a core material for sandwich structure even with different skin thickness or layer without reducing performances or roles of the core. The experimental results also clearly show that with appropriate facesheet/ skin will directly influence the overall performance of sandwich structures. This new core composite material is found not only compatible with the synthetic composite but has several advantages when compared such as minimum health issue involved, environmentally friendly and better economical factor. ACKNOWLEDGMENT The authors would like to thank the Faculty of Manufacturing Engineering in Universiti Teknikal Malaysia Melaka (UTeM) and its financial support under Grant PJP/2011/FKP (3A) S00870. REFERENCES [1] Ashby, M.F., Hugh, S. and David, C. (2007): Materials - Engineering, Science, Processing and Design. UK:

Elsevier Ltd, pp.473-474. [2] Bella, G.D., Calabrese, L. and Borsellino, C. (2012): Mechanical characterisation of a glass/polyester

sandwich structure for marine applications, Materials & Design, Vol.42, pp.486-494. [3] Butukuri, R.R., Bheemreddy, V.P., Chandrashekhara, K. and Samaranayake, V.A. (2012): Evaluation of Low-

Velocity Impact Response of Honeycomb Sandwich Structures using Factorial-Based Design of Experiments, Journal of Sandwich Structures and Materials, Vol.14, No.3, pp.339-361.

[4] Eekhout, M. (2010): Composite Stressed Skin Roofs for Liquid Design Architecture, International Journal of Structural Engineering, Vol.1, Iss.3, pp.255-279.

[5] Erian, A. (2004): American Society for Composites / American Society for Testing and Materials Committee., DEStech Publication, Inc., USA, p.25.

[6] Erik, L. (2010): Industrial Plastics: Theory and Applications, 5th edition, Delmar Cengage Learning, USA, p.231, p.505.

[7] Jeyakrishnan, P.R., Chockalingam, K.K.S.K. and Narayanasamy, R. (2013): Studies on Buckling Behavior of Honeycomb Sandwich Panel, The International Journal of Advanced Manufacturing Technology, Vol.65, Iss.5-8, pp.803-815.

[8] Kha, M.K. (2006): Compressive and Lamination Strength of Honeycomb Sandwich Panels with Strain Energy Calculation from ASTM Standards, Journal of Aerospace Engineering, Vol.220, No.5, pp.375-386.

[9] Kim, H.Y. and Lee, S.Y. (2012): A Steel-reinforced Hybrid GFRP Deck Panel for Temporary Bridges, Construction and Building Materials, Vol.34, pp.192-200.

[10] Ku, H., Wang, H., Pattarachaiyakoop, N. and Trada, M. (2011): A Review on the Tensile Properties of Natural Fiber Reinforced Polymer Composites, Composites Part B: Engineering, Vol.42, Iss.4, pp.856-873.

[11] Lagace, P.A. and Mamorini, L. (2000): Factors in the Compressive Strength of Composite Sandwich Panels with Thin Facesheets, Journal of Sandwich Structures and Materials, Vol.2, No.4, pp.315-330.

[12] Lebée, A. and Sab, K. (2012): Homogenization of Thick Periodic Plates: Application of the Bending-Gradient Plate Theory to a Folded Core Sandwich Panel, International Journal of Solids and Structures, Vol.49, Iss.19–20, pp.2778-2792.

[13] Lefebvre, L.P, Banhart, J. and Dunand, D.C. (2008): Porous Metals and Metallic Foams - Current Status and Recent Developments, Advanced Engineering Materials, Vol.10, No.9, pp.775-787.

[14] Leong, Y.W., Abu Bakar, M.B., Mohd Ishak, Z.A. and Ariffin, A. (2003): Mechanical and Morphological Study of Talc/Calcium Carbonate Filled Polypropylene Hybrid Composites Weathered in Tropical Climates, Jurnal Teknologi, Vol.39(A), pp.23-34

[15] Menezes, P.L., Rohatgi, P.K. and Lovell, M.R. (2012): Studies on the Tribological Behavior of Natural Fiber Reinforced Polymer Composite: Green Tribology, Springer Berlin Heidelberg, pp.329-345.

[16] Menta, V.G.K, Vuppalapati, R.R., Chandrashelhara, K., Pfitzinger, D. and Phan, N. (2012): Manufacturing and Mechanical Performance Evaluation of Resin-Infused Honeycomb Composites, Journal of Reinforced Plastics and Composites, pp.415-423, doi:10.1177/0731684412439792

[17] Okada, T., Caprace, J.D., Estefen, S.F., Han, Y., Josefson, L., Kvasnytskyy, V.F., Liu, S., Papazoglou, V., Race, J., Roland, F., Schipperen, I., Wan, Z. and Yu, M. (2009): Materials and Fabrication Technology, Proceeding of 17th International Ship & Offshore Structures Congress, 16-21 August, Seoul, Korea, Vol.2, pp.137-200.

[18] Pandya, K.S., Veerraju, C. and Naik, N.K. (2011): Hybrid Composites Made of Carbon and Glass Woven Fabrics under Quasi-Static Loading, Materials & Design, Vol.32, Iss.7, pp.4094-4099.

[19] Park, C.H., Saouab, A., Bréard, J., Han, W.S., Vautrin, A. and Lee, W.I. (2009): An Integrated Optimisation for the Weight, the Structural Performance and the Cost of Composite Structures, Composites Science and Technology, Vol.69, Iss.7–8, pp.1101-1107.



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[20] Reany, J. (2009): Corrugated Skin Composite Sandwich Panels. UMI Microform 3358111, ProQuest LLC, USA: p.60.

[21] Rhymer, J., Kim, H. and Roach, D. (2012): The Damage Resistance of Quasi-Isotropic Carbon/Epoxy Composite Tape Laminates Impacted by High Velocity Ice, Composites Part A: Applied Science and Manufacturing, Vol.43, Iss.7, pp.1134-1144.

[22] Robert, K.B. (2006): Frontal Polymer Research, Nova Science Publishers, New York, p.189. [23] Scott, E.S. and Daniel, O.A. (2011): Structural Enhancements for Increased Energy Absorption in Composite

Sandwich Structures, Journal of Sandwich Structures and Materials, Vol.13, No.2, pp.137-158. [24] Sezgin, F.E., Tanoğlu, M., Eğilmez, O.Ö., Dönmez, C. (2010): Mechanical Behavior of Polypropylene-based

Honeycomb-Core Composite Sandwich Structures, Journal of Reinforced Plastics and Composites, Vol.29, No.10, pp.1569-1579.

[25] Thomas, S., Kuruvilla, J., Malhotra, S.K., Koichi, G. and Sreekala, M.S. (2012): Polymer Composites, Macro- and Microcomposites, India: Wiley-VCH, Vol.1, p.692.

[26] Tognana, S., Salgueiro, W., Somoza, A., Pomarico, J.A. and Ranea-Sandoval, H.F. (2009): Influence of the Filler Content on the Thermal Expansion Behavior of an Epoxy Matrix Particulate Composite, Materials Science and Engineering: B, Vol.157, Iss.1–3, pp.26-31.

[27] Vinson, J.R. and Sierakowski, R.L. (2008): Introduction To Composite Materials - The Behavior of Structures Composed of Composite Materials, Solid Mechanics and Its Applications, Springer Netherlands Publisher, Vol.105, pp.1-38.

[28] Wang, Y., Li, J., Song, K. and Ye, B.Q. (2012): The Study of the Precision Grinder Bed Thickness with Artificial Granite Composite, Applied Mechanics and Materials, Vol.120, pp.403-409.

GLOBAL ENGINEERS & TECHNOLOGISTS REVIEW

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UMAR NIRMAL1, JAMIL HASHIM2 and SANJEEV KUMAR3

1, 2, 3 Centre of Advance Materials and Green Technology

Faculty of Engineering and Technology

Multimedia University

Jalan Ayer Keroh Lama, 75450, Melaka, MALAYSIA [email protected]

[email protected]

1.0 INTRODUCTION The problem of solid waste management, particularly, used automobile tires has been an ever escalating problem worldwide (Clark et al., 1993). It is no exception here in Malaysia as approximately 8.2 million scrapped tires are generated annually (Manuel and Dierkes, 1997; Dick, 2001). Solid waste materials such as scrapped tires are being produced and its accretion in enormous quantities is causing a growing concern to the environment (Manuel and Dierkes, 1997). Scrapped tires are non-decomposing material that undermines the environment (Son et al., 2011). The conventional methods of disposing scrapped tires in landfills is becoming unacceptable due to the rapid exhaustion of accessible land for better usage (Snyder, 1998). Besides that, there is no current institutional approach for managing scrapped tires as a useful resource in Malaysia and there is no sufficient awareness regarding recycling of used automobile tires (Manuel and Dierkes, 1997). Furthermore, efficient legislation by means of respect to the local reprocess of waste materials does not exist in Malaysia yet (Manuel and Dierkes, 1997; Dick, 2001). Innovative techniques on the matter of recycling are being experimented by researchers around the world as solutions to cope with the tire disposal problem. Many have demonstrated effectiveness in shielding our environment and natural resources (Pelisser et al., 2011). Nonetheless, an encouraging technique for getting rid of this non-decomposing material is to use it as part of construction material such as concrete (Atahan and Yücel, 2012; Chou et al., 2010; Lu et al., 2007; Aules, 2011). Many researchers in recent years have carried out works to incorporate used tires with concrete. Amid the alternatives that show the most potential is the use of reprocessed ground tire rubber as replacement for aggregate in concrete matrix (Gan, 1997; Ganjian et al., 2009). The rubberized concrete composite material is known as “rubcrete” (Atahan and Yücel, 2012; Chou et al., 2010; Lu et al., 2007; Aules, 2011). Previous researches have recorded different compressive strength results mainly due to the type and size of rubber crumbs used in their rubberized concrete mixture. Research conducted by Khaloo in year 2008 indicated that the eventual compressive strength diminishes considerably through escalating amount of rubber deliberation, and the strengths for every single one of the mixes come within reach of a bare minimum of 1 MPa (Khaloo et al., 2008). Khaloo described that the methodical drop of final compressive strength of rubberized

ABSTRACT

This research paper studies the feasibility of rubcrete composites and their performance incorporating of 10 %, 20 % and 30 % shredded used tires by volume as replacement for coarse aggregates. From literature review, studies showed no similar research had been carried out on rubcrete under the revised ISO 1920-4:2005 standard testing of concrete. Studies were conducted to examine the compressive strength and physical deformation of test specimens for the 7th and 28th day cure using two sets of control specimens (pure concrete) and rubberized specimens (rubcrete). Results showed a dropped in compressive strength by at least 20 % for each 10 % increment of shredded used tires. Buckling at the sides of the rubberized specimens under vertical load was observed; however they rebounded inwards once vertical load was released compared to the control specimen which experienced complete plastic deformation. The study shows that, with proper shredded rubber and concrete matrix, formation of ductile concrete is possible. Keywords: Used Tires, Shredded Rubber, Rubcrete, Compressive Strength, Concrete, Ductile. Article History: Received 3 June 2014, Accepted 18 July 2014.

FEASIBILITY STUDY OF RUBCRETE COMPOSITE USING USED SHREDDED RUBBER: EVALUATION OF COMPRESSIVE

STRENGTH AS PER ISO 1920-4:2005 STANDARD



9

0mm 15mm

concrete may confine the employ of crumb and or rubber particles as a replacement for fine and coarse aggregate from not exceeding 25 % of the total volume it replaces, his research highlighted this crucial factor mainly for structural applications (Khaloo et al., 2008; Muhammad et al., 2012). An experiment by Ganjian in early 2009 found that the ideal testing for compressive strength was on the 7th and 28th day after curing of test specimen (Ganjian et al., 2009). His results were in line with Khaloo’s findings whereby the compressive strength of concrete mixtures incorporated with chipped rubber had dropped (Ganjian et al., 2009; Khaloo et al., 2008). Ganjian discussed that the drop in compressive strength was primarily caused by drop in the cement content in these mixtures (Ganjian et al., 2009). An experiment by Toutanji carried out in 1996, where the effect of replacing coarse aggregate with rubber aggregate on the compressive strength was recorded and discussed (Toutanji, 1996). Unlike Ganjian’s experiment, Toutanji replaced larger percentages of the coarse aggregate with rubber aggregates ranging from 0 to100 % (Ganjian et al., 2009; Toutanji, 1996). He recorded losses up 75 % when 100 % of rubber aggregates were used to replace the coarse aggregates (Toutanji, 1996). Nevertheless, the findings of Ganjian’s research was in line with the research done by Khaloo in 2008 and revealed that adding up to five percent of recycled tire rubber does not have an enormous negative implications on rubcrete compressive strength (Ganjian et al., 2009; Khaloo et al., 2008). The increment of compressive strength loss starts after ten percent of the total coarse aggregate is replaced by weight. Although there have been much research and work on the application and physical analysis of rubcrete, the use of the revised ISO 1920-4:2005 standard which defines testing of concrete has yet to be analysed (Bungey et al., 2006). As a result of the finding, this research seeks to determine the feasibility of using rubcrete composites under the guidelines set in the standard mentioned above (Bungey et al., 2006). For the current work, shredded rubber particles will be used as reinforcements with different weight fractions (i.e. 10 to 30 %) against concrete mixture. Consequently, experimental works will be performed to study the variation of compressive strength for the rubcrete test specimen against the control specimen (0 %), the findings would be then used to recommend the optimal rubber replacement percentage against compressive strength loss.

2.0 MATERIALS AND METHODS The shredded rubber in two standard bags weighing 25 kg each was obtained from GL Rubber Industries at state of Selangor, Malaysia. The average size of the shredded rubber was 15 mm as shown in Figure 1. Small contaminants such as unwanted foreign materials and rubber with synthetic cotton still attached were removed from the raw shredded rubber. The contaminants free shredded rubber was washed using running water in small portions as to enable proper cleaning of all raw shredded rubber particles.

Figure 1: (a) Shredded rubber particles, (b) 15 mm.

2.1 Preparation of Control and Rubberized Concrete Samples

The control concrete sample of grade M-25 was prepared based on the design mix as per IS-10262-2009. The raw materials such as water, cement, fine and coarse aggregates and admixtures were weighed according to the mix calculation which was based on the minimum cement content of 310 kg/m3 and placed into a concrete mini mixer in small portions until a volume of 0.15 m3 and allowed to mix properly to avoid clumping of materials. Once the control sample was ready, a second batch of three different rubberized concrete samples which would replace the coarse aggregate by ascending percentage weight of 10 %, 20 %, and 30 % was prepared. In order to accommodate the addition of the shredded rubber, the design mix was altered by reducing the weight of the coarse aggregate and replacing the reduced weight with the shredded rubber.

(a) (b)



10

2.2 Preparation of Test Specimens The preparation of the test cube specimens involved two stages which include the making and curing of the test cubes. The sequences of steps used in the two stages of test cube preparations are in line with the ISO 1920-3:2004 standard which specifies the shape and dimensions of concrete test specimens for strength tests and the methods of making and curing these test specimens. Eight test cube moulds measuring 150 x 150 x 150 mm3 were cleaned and prepared by removal of hardened concrete on the surface of the cube moulds for the 7th day compressive strength test. The cubes were made in a room with ambient temperature of 28 °C ± 5 °C and relative humidity of 90-95 % ± 2 %. Silicone-free lubricant and release agent with low viscosity and temperature resistance from -20°C to +130°C was sprayed into each mould cavity as to prevent the fresh samples of control and rubberized concrete from sticking to the mould surface. Two moulds each were filled with fresh samples of control concrete by a gradual increment of one third until full separated by three intervals of 35 strokes using an iron rod, followed by two moulds each of the 10 %, 20 % and 30 % rubberized concrete samples. The steps were repeated to produce cubes for the 28th day compressive strength test. In total, sixteen test cube specimens were made for 7th and 28th day testing. 2.3 Experimental Procedure Slump test using a standard slump test mould was carried out for each sample of control and rubberized concrete that was batched using the mini mixer. The testing of the test cube specimens were carried out in accordance with the ISO 1920-4:2005 standard which specifies procedures for testing the strength of hardened concrete. The test cubes for the 7th day test were taken out of the water tank exactly 7 days from the date they were made and wiped off any excess water on the surface using a cloth after which they were left to air dry for several minutes. All eight test specimens comprising of the control and rubberized concrete cubes were tested within 2 and a half hours from the time they were taken out of the curing tank as specified by the ISO 1920-4:2005 standard. Each cube was weighed using a weighing scale and the readings were taken for analysis. The cube testing machine used was of model ASEW 101 which had a 2000 kN compressive load capacity is calibrated by Lafarge Concrete Malaysia every six months and operated by hydraulic pressure. The calibration of the test machine is important as it is specified in the ISO 1920-4:2005 standard. The mix of grade M-25 concrete as per IS-10262-2009 is shown in Table 1 while the mix calculation for control concrete sample and rubberized concrete sample is shown in Table 2 and Table 3 respectively.

Table 1: Design mix of grade M-25 concrete as per IS-10262-2006.

Specifications for Proportioning

Grade Description M-25

Cement Type OPC 53 Grade

Maximum Water Cement Ratio 0.45

Maximum Cement Content 540 kg/m3

Minimum Cement Content 310 kg/m3

Maximum Nominal Aggregate 20 mm

Workability (Slump) 75 mm ±25 mm

Type of Chemical Admixture Super Plasticizer

Table 2: Mix calculation for control concrete sample.

Material Weight (Kg) = Density (ρ) x Volume (m3)

Cement 3150 x 0.015 = 47.25

Water 1000 x 0.0207 = 20.70

Admixture 1000 x 0.000201 = 0.20

Coarse Aggregate 2884 x 0.07065 = 203.75

Fine Aggregate 2605 x 0.0432 = 112.54



11

Table 3: Mix calculation for rubberized concrete sample.

Material Weight (Kg) = Density (ρ) x Volume (m3)

Cement 3150 x 0.015 = 47.25

Water 1000 x 0.0207 = 20.70

Admixture 1000 x 0.000201 = 0.20

Fine Aggregate

2605 x 0.0432 = 112.54

Coarse Aggregate

90 % 0.9 x 2884 x 0.07065 = 183.375

80 % 0.8 x 2884 x 0.07065 = 165.000

70 % 0.7 x 2884 x 0.07065 = 142.625

Shredded Rubber Granules (old weight -new weight)

10 % 203.75 - 183.375 = 20.375

20 % 203.75 - 165.000 = 38.75

30 % 203.75 - 142.625 = 61.12

The test cube specimens were placed inside the testing machine properly in the sequence of control, 10 %, 20 % and 30 % rubberized cubes. The testing machine was operated in the following sequence; the power was turned on, the force indicating arrow on the pressure gauge was set to zero, the pressure adjust valve was opened and the start button was pressed to apply vertical load on the test specimen. As vertical load was being applied, the force on the pressure gauge was recorded at five second intervals until the specimen reached its final compressive strength. At the same time, snapshot images were taken using a camera (model: Samsung Galaxy Camera EX-GC100) at these intervals to observe the deformation of the test cubes as vertical load is applied gradually. The readings and images obtained from the testing of all eight test cube specimens were tabulated for analysis and discussion. The steps above were repeated for the eight test cube specimens for the 28th day compressive strength test. The rubcrete composite surface morphology was studied using a scanning electron microscopy (SEM) model: JEOL, JSM 840. For SEM, the specimens’ surfaces were gold coated before starting the scanning process using an ion sputtering device; model: JEOL, JFC-1600.

3.0 RESULTS AND DISCUSSION The results obtained from the experiment have been categorised into two parts namely the analysis of the compressive strength test and slump test for the 7th and 28th day tests. The collective average of all specimens were plotted and compared with the physical deformation of each specimen according to the rubber-concrete ratio of control cube (0 %), 10 %, 20 % and 30 %. The following are the detailed analysis of the experiment.

3.1 Effect of the Rubber Addition on the Workability of the Rubcrete The workability of concrete was determined by means of slump test. From Table 4, it can be observed that the slump reading for the control specimen is in line with a standard slump reading for concrete of grade M-25 which is 75mm +/- 25mm. It can be observed that the 10 % coarse aggregate replaced by rubber has very little influence on the slump reading hence the workability remains the same as the control. However, the 20 % and 30 % rubber replacing coarse aggregate have a significantly lower slump reading especially the 30 % rubcrete mix. The 30 % rubcrete mix was very difficult to be formed and compacted into the cube moulds. The workability of the mix had drastically decreased with the increase of rubber replacement as the shredded rubber pieces were not flowing well with the cement paste.

Table 4: Slum reading for different batches according to testing days.

Batch Slump (mm) ±25

7 days 28 days

Control 75 75

10 % 70 75

20 % 50 55

30 % 25 30



12

3.2 Weight Reduction of Rubberized Concrete Specimens The specimens made for both the 7th and 28th day testing showed gradual decrease in weight compared to the control specimen which had an average weight of 8 kg. As the percentage of rubber replacing coarse aggregate is increased by 10 %, 20 % and 30 %, the weight of the specimens dropped by average of 7.5 %, 19 %, and 31 %. This is due to rubber granules having lower density compared to the coarse aggregate which has higher density. 3.3 Compressive Strength for 7th Days Test From Figure 2(a), the base reading of 600 kN and 650 kN are obtained for the control specimen for both sample 1 and 2 respectively. This reading is in line with the industrial standard for a grade M-25 concrete test cube on the 7th day test. The specimens were able to increasingly withstand compressive load until ultimate failure occurred at time interval 20 second. This finding can be observed in the other three rubcrete matrix of 10 %, 20 % and 30 % as illustrated in Figures 2(b), 2(c) and 2(d). The chart as in Figure 2(b) shows approximately 30 % drop in final compressive strength achieved by both samples for the 10 % rubber concrete ratio as compared to the control specimen in Figure 2(a). Similar observations can be seen from Figures 2(c) and 2(d), however in these matrixes of 20 % and 30 % rubber replacing coarse aggregate an elevated drop of 65 % and 85 % respectively in compressive strength compared to the control specimen. From Figure 2(d), it can be observed that both samples tested produced almost identical reading compared to Figures 2(a), 2(b) and 2(c) where either one of the samples tend to produce a linearly increasing reading and the other would always be of slightly higher reading.

Figure 2: Effects of replacing coarse aggregate with shredded rubber on the compressive strength for different rubber mesh compositions and control specimen for 7th day test (a) control cube, (b) 10 % mesh, (c) 20 % mesh, and (d) 30 % mesh.

The gradual increase in rubber replacing the coarse aggregate by percentage weight directly influences the decrease in final compressive strength of each specimen as seen in Figures 2(b), 2(c) and 2(d). This phenomenon was also observed in the previous research done by Khaloo et al. (2008). A drop in final compressive strength is imminent as rubber is much softer compared to the harder coarse aggregate. The drastic drop in final compressive strength is much higher compared to the work carried out by Toutanji (1996) where by 100 % rubber replacing coarse aggregate indicated a loss of up to 75 % in final compressive strength (Ganjian et al., 2009; Toutanji, 1996). Compared to the 85 % drop in final compressive strength with only 30 % rubber replacing coarse aggregate as seen in Figure 2(d). This large difference in drop of final compressive strength could be credited to the grade of concrete used in Toutanji’s experiment (Ganjian et al., 2009; Toutanji, 1996).



13

3.4 Physical Deformation of Specimens against Average Compressive Strength for 7th Days Test The average compressive strength versus time interval is presented in Figure 3. From Figure 3, the gradual decrease in final compressive strength as an average for both samples can clearly be seen as the final compressive strength of the control specimen represented by the dotted line is far superior to that of the 10 %, 20 % and 30 % rubber replacing coarse aggregate. The images seen in Figures A1(a)-(d) are directly related to the four points labelled on each line present in the chart of Figure 3. The points labelled in ascending order directly reflect the time intervals of five second increments at which point an image was captured to demonstrate the deformation of the test specimens accordingly.

Figure 3: Average compressive strength for control cube and the different rubber matrix compositions for the 7th day test.

From Figure A1(a - A1), the test specimen of 10 % rubber replacement experienced no deformation for the first 5 seconds during which vertical load was applied. This was the case for the 20 %, 30 % rubber replacement and control specimen as illustrated in Figures A1(b - B1, c - C1, d - D1). At time interval of 10 seconds, at least one crack was seen in all specimens as indicated by the arrows in Figures A1(a - A2, b- B2, c - C2, d - D2). The 10 % specimen behaved similar to the control specimen in which case both started to develop macro cracks once 15 seconds had elapsed as seen in Figures A1(a - A3, d - D3). However, from the image in Figure A1(d - D4), it can be observed that the control specimen went on to develop macro cracks and experienced complete failure when the top right corner of the cube burst open. The 20 % specimen seen in Figure A1 (b - B3) developed more cracks at the 15 second interval and there cracks became large when the cube eventually reach ultimate compressive strength at 20 second time interval as seen in Figure A1(b - B4). One can see from Figures A1(c - C3, c - C4) that the cracks widen larger but more cracks do not seem to occur as time elapses. It can be seen in Figures A1(a, b, c) that the specimens containing rubber do not burst open as the control cube seen in Figure A1(d - D4). It was also observed that the specimens with higher rubber content experienced less cracks, as the cracks only continued to expand wider as time elapsed. Similar observations were made in previous works namely that of Toutanji (1996) who concluded that the rubberized concrete specimens were able to withstand large deformations (Toutanji, 1996; Sukontasukkul and Chaikaew, 2006). The shredded rubber pieces inside the specimens seem to act as tiny spring that absorb some of the compressive load placed upon it prior to reaching its final compressive strength (Sukontasukkul and Chaikaew, 2006). Although this ability of the rubberized concrete specimen is noteworthy, the ultimate compressive strength achieved by the control specimen prior to failure is far greater.

From Figures A1(a - A2, b - B3, c - C3), the hollow red circles show the crucial areas that SEM images were taken. The corresponding SEM images from Figure 4 show the debonding that the rubber experiences. Figure 4(a) shows a small area with small rubber particles broken off due to the improper bonding between cement paste and rubber granules. From Figures 4(b) and Figure 4 (c), it can be observed that the debonding area has increased substantially. As the percentage of rubber replacing coarse aggregate increases, the de-bonding experienced by the rubber granules also seems to increase. Figure 4(c) shows the large piece of exposed rubber granule that has lead to the macro crack seen in the hollow red circle from Figure A1(c - C3).



14

C

e

R

Db

Figure 4: SEM images showing rubber and concrete composition at different matrix (a) 10 %, (b) 20 %, and (c) 30 %. Remark: Db – debonding, Ce – cementitious, R – rubber, ExRb – exposed rubber.

3.5 Compressive Strength for 28th Days Test From Figure 5(a), the base reading of 750 kN and 700 kN are obtained for the control specimen for both sample 1 and 2 respectively and the readings meet the target reading specified by the design mix for grade M-25 concrete on the 28th day compressive strength test. This is an increase of almost 15 % as compared to the final compressive strength obtained on the 7th day compressive test as shown in Figure 2(a). With comparison to the Figures 2(b), 2(c), 2(d), an increase of 20 %, 33.3 % and 50 % in final compressive strength was observed in the three rubcrete matrix of 10 %, 20 % and 30 % respectively as illustrated in Figures 5(b), 5(c) and 5(d).

Figure 5: Effects of replacing coarse aggregate with shredded rubber on the compressive strength for different rubber mesh compositions and control specimen for 28th day test (a) control cube, (b) 10 % mesh, (c) 20 % mesh, and (d) 30 % mesh.

Similar to the findings of the 7th day test, Figure 5(b) shows approximately 30 % drop in final compressive strength achieved by both samples for the 10 % rubber concrete ratio as compared to the control specimen in Figure 5(a), Figures 5(c) and Figure 5(d) shows an elevated drop of 57 % and 71 % in compressive strength compared to the control specimen matrix of 20 % and 30 % rubber replacing coarse aggregate respectively. In comparison to the 7th day test, the 28th day test showed similar decrease in final compressive strength of each specimen as being directly influenced by the increase of rubber replacing coarse aggregate by percentage weight as shown in Figures 5(b)-(d). The increase of final compressive

(a) (b)

Ce

R

Db

Ce R

(a) (c)

Ce

R

Ce

R

Db

Ex Rb

Ce

R

(c)



15

Cr

Cr

Ce

R

Cr

Ce

R

strength for all samples for the 28th day test is due to the longer curing time that allowed the test cubes to achieve better setting and hardness. 3.6 Physical Deformation of Specimens against Average Compressive Strength for 28th Days Test From Figures A2(a) and A2(d), it is observed that the 10 % rubber specimen deforms and develops cracks similar to the control specimen although the compressive strength achieved by the specimens are different as seen in Figure 6. This is because the rubber content in the specimen is very little thus its deformation is very similar to that of the control specimen. However, the control specimen develops macro cracks and experiences failure at the top right corner of the test cube as seen in Figure A2(d - D4). From Figures A2(b) and A2(c), the specimens develop significantly fewer cracks compared to the control specimen in Figure A2(d). Despite an unfavorable impact on compressive strength, the increase in rubber content improves behavior during the plastic phase.

Figure 6: Average compressive strength for control cube and the different rubber matrix compositions for the 28th day test.

The sequence of images from Figure A2(c) clearly exhibit the load deflecting capability of highly rubberized concrete whereby there is only one crack that is visible and this single crack only became larger as time progressed. From Figure 7, the hollow red circles show the crucial areas that scanning electron microscope (SEM) images were taken. The corresponding SEM images from Figure 7 show the gradual decrease in cement between the rubber at its border line with the fine and coarse aggregate. From Figure 7(a), the cement paste covers the aggregate and rubber particles completely except for the appearance of a small crack.

Figure 7: SEM images showing rubber and concrete composition at different matrix (a) 10 %, (b) 20 %, and (c) 30 %. Remark: Cr - crack, Ce – cementitious, R – rubber.

As the percentage of rubber replacing coarse aggregate is increased, an increase in the number of cracks and the significantly large cracks can be observed as seen in Figures 7(b) and 7(c). These crucial areas developed micro cracks as seen in the SEM images in Figure 7, thus leading to the development of larger crack that can be seen by the naked eye as observed in Figure A2(a - A2, b - B3, c - C2).

(a) (b) Cr

Cr

C

e

R

(c)



16

Bc

Unloaded

10 %

Rb

(b) 1

Loaded

10 %

Ma Cr

Cr

Bc

Bc

2

Unloaded

10 %

3

(c)

Unloaded Unloaded Loaded

20 %

20 %

20 %

Rb

Bc

Bc

Ma Cr

Ma Cr

1 2 3

(d) 2

Unloaded Unloaded Loaded

30 %

30 %

30 %

Rb

Bc

Ma Cr

1 3

Unloaded

Control

Unloaded

Control

Loaded

Control

Fr

Lg Fg

Sm Fg

Ma Cr

Cr

(a) 1 2 3

3.7 Proposed Wear Mechanism for the Control and Rubcrete Composite Before, During and After the Compressive Test From Figures 8(a1, b1, c1 & d1), the unloaded test specimens are similar in size and shape. However as seen in Figures 8(b1, c1 & d1), the rubberized concrete test specimens have rubber granules that can be seen on the surface of the test specimens, the concentration of these rubber granules increase as the percentage of rubber replacing coarse aggregate increases. Figure 8(a2) shows the deformation and failure experienced by the control test specimen which forms micro and macro cracks on the surface, fractures on the sides and produces small and large fragments.

Figure 8: Control and rubberized test cubes before (1), during (2), and after (3), according to different matrix content (a) control

cube, (b) 10 %, (c) 20 %, and (d) 30%. Remark: Bc –buckling, Sm Fg – small fragment, Lg Fg – large fragment.



17

Figure 8(b - 2) shows the behaviour of the 10 % rubber test specimen that is similar to that of the control cube except that no fracture is experienced; instead slight bucking is observed at the side surface of test cube as vertical load increases. Similar observations were made for the 20 % and 30 % test specimens as seen in Figures 8(c – 2, d - 2); however the buckling effect was much more significant in these two test specimens with the 30 % rubber test specimen exhibiting the greatest buckling effect as compared to the other three test specimens. From Figures 8(c – 2, d - 2), the test specimens under vertical load were observed to have less micro and macro cracks, whereby the 30 % rubber specimen in Figures 8(d - 2) only had one macro crack that expanded slightly while under vertical load. The most interesting findings were the fact that all the rubberized test specimens contracted to a certain degree, as Figures 8(b - 3) shows the 10 % specimen returned to its original shape as compared to the control specimen which was badly fractured as seen in Figure 8(a - 3). From Figures 8(c – 3, d - 3), a more significant morph in shape was observed as the 20 % and 30 % specimens contracted by a large extent considering the buckling experienced under vertical load. This phenomenon of buckling under load opposed to fracture by the rubberized specimens could be attributed to the spring effect of the rubber particles imbedded within the concrete. This failure mode can be explained by the ability to withstand large vertical loads before failurethus allowing for the rubberized specimens to contract inwards once vertical load was disengaged.

4.0 CONCLUSION The work conducted during this research focuses on the feasibility of using shredded rubber as a direct replacement for coarse aggregate in concrete matrix. The results of the compressive strength test for the 7th and 28th day; and physical deformation of test specimens during testing led to the following conclusions:

i) The final compressive strength of the 10 %, 20 %, and 30 % rubberized rubcrete dropped by 30 %, 65 %, and 85 % respectively as compared to the control test specimen for the 7th day test.

ii) The final compressive strength on the 28th day test of the 10 %, 20 %, and 30 % rubberized rubcrete had increased by 20 %, 33.33 % and 50 % respectively compared to the final compressive strength of the rubberized rubcrete on the 7th day test. However, final compressive strength dropped by 30 %, 57 % and 71 % for the10 % and 20 %, 30 % rubberized rubcrete respectively compared to the control test specimen for the 28th day test.

iii) The 10 % rubber replacing coarse aggregate specimens on both the 7th and 28th day tests achieved the highest final compressive strength whereas the 30 % rubberized rubcrete experienced the highest drop in final compressive strength on both testing dates.

iv) The increase in rubber replacing coarse aggregate directly affects the drastic escalation of drop in

final compressive strength of all rubberized test specimen compared to the control specimen.

v) The rubberized rubcrete experienced buckling at the sides of the specimen compared to the control specimen that experienced fracture and fragmentation.

vi) The rubberized test specimens had less micro and macro cracks compared to the control

specimens; they were also able to contract inwards once vertical load was released with slightly buckled sides.

REFERENCES [1] Atahan, A.O. and Yücel, A.Ö. (2012): Crumb Rubber in Concrete: Static and Dynamic Evaluation,

Construction and Building Materials, Vol.36, pp.617-622. [2] Aules, W.A. (2011): Utilization of Crumb Rubber as Partial Replacement in Sand for Cement Mortar,

European Journal of Scientific Research, Vol.51, No.2, pp.203-210. [3] Bungey, J.H., Grantham, M.G. and Millard, S. (2006): Testing of Concrete in Structures - 4th Edition, CRC

Press. [4] Chou, L.H., Lin, C.N., Lu, C.K., Lee, C.H. and Lee, M.T. (2010): Improving Rubber Concrete by Waste Organic

Sulfur Compounds, Waste Management & Research, Vol.28, No.1, pp.29-35. [5] Clark, C., Meardon, K. and Russell, D. (1993): Scrap Tire Technology and Markets, Park Ridge - Noyes Data

Corporation. [6] Dick, J.S. (2001): Rubber Technology - Compounding and Testing for Perfomance, Hanser Publishers,

Munich.



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[7] Gan, M.S.J. (1997): Cement and Concrete, CRC Press. [8] Ganjian, E., Khorami, M. and Maghsoudi, A.A. (2009): Scrap-Tyre-Rubber Replacement for Aggregate and

Filler in Concrete, Construction and Building Materials, Vol.23, Iss.5, pp.1828-1836. [9] Khaloo, A.R., Dehestani, M. and Rahmatabadi, P. (2008): Mechanical Properties of Concrete Containing a

High Volume of Tire - Rubber Particles, Waste Management, Vol.28, Iss.12, pp.2472-2482. [10] Lu, C.K., Chang, J.R. and Lee, M.T. (2007): Use of Waste Rubber as Concrete Additive, Waste Management

and Research, Vol.25, No.1, pp.68-76. [11] Manuel, H.J. and Dierkes, W. (1997): Recycling of Rubber - Volume 99 of Rapra Report, iSmithers Rapra

Publishing. [12] Muhammad, B., Ismail, M., Bhutta, M.A.R. and Zaiton, A.M. (2012): Influence of Non-Hydrocarbon

Substances on The Compressive Strength of Natural Rubber Latex-Modified Concrete, Construction and Building Materials, Vol.27, Iss.1, pp.241-246.

[13] Pelisser, F., Zavarise, N., Longo, T.A. and Bernardin, A.M. (2011): Concrete Made with Recycled Tire Rubber: Effect of Alkaline Activation and Silica Fume Addition, Journal of Cleaner Production, Vol.19, Iss.6-7, pp.757-763.

[14] Snyder, R.H. (1998): Scrap Tire - Disposal and Reuse, Report Number R-158, Society of Automotive Engineers, PA, USA.

[15] Son, K.S., Hajirasouliha, I. and Pilakoutas, K. (2011): Strength and Deformability of Waste Tyre Rubber-Filled Reinforced Concrete Columns, Construction and Building Materials, Vol.25, Iss.1, pp.218-226.

[16] Sukontasukkul, P. and Chaikaew, C. (2006): Properties of Concrete Pedestrian Block Mixed with Crumb Rubber, Construction and Building Materials, Vol.20, Iss.7, pp.450-457.

[17] Toutanji, H.A. (1996): The Use of Rubber Tire Particles in Concrete to Replace Mineral Aggregates, Cement and Concrete Composites, Vol.18, Iss.2, pp.135-139.



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APPENDIX

Cr Cr

Ma Cr

Ma Cr

Ma Cr Ma Cr

Ma Cr

Ma Cr

Cr

Cr

Cr

Cr Ma Cr

Ma Cr

Ma Cr

(a) 10 %, A1 (a) 10 %, A2

(a) 10 %, A3 (a) 10 %, A4

(b) 20 %, B1 (b) 20 %, B2

(b) 20 %, B3 (b) 20 %, B4



20

Figure A1: Images showing test cube deformation corresponding to data points on Figure 3, (a) 10 %, (b) 20 %, (c) 30 %, and (d) control cube. Remark: Hollow red circles represent crucial spots where the SEM images were taken, (Cr: crack, Ma Cr: macro crack, Fr: fracture).

Cr

Cr

Ma Cr

Ma Cr

Ma Cr

Ma Cr

(c) 30 %, C1 (c) 30 %, C2

(c) 30 %, C3 (c) 30 %, C4

Cr Cr

Ma Cr

Cr

Cr

Cr

Ma Cr Ma Cr

Cr

Fr

Cr

Fr

(d) control cube, D1 (d) control cube, D2




21

Cr

Cr

Cr

Cr Cr

Ma Cr Cr

Cr

Cr

(a) 10 %, A1 (a) 10 %, A2

(a) 10 %, A3 (a) 10 %, A4

Cr

Cr Cr

Cr

Cr

Cr

Ma Cr

Ma Cr

Cr

(b) 20 %, B1 (b) 20 %, B2

(b) 20 %, B3 (b) 20 %, B4



22

Figure A2: Images showing test cube deformation corresponding to data points on Figure 6, (a) 10 %, (b) 20 %, (c) 30 %, and (d) control cube. Remark: Hollow red circles represent crucial spots where the SEM images were taken, (Cr: crack, Ma Cr: macro crack, Fr: fracture).

Cr

Cr Ma Cr

(c) 30 %, C1 (c) 30 %, C2

(c) 30 %, C3 (c) 30 %, C4

Cr

Cr

Cr

Cr

Cr

Ma Cr

Ma Cr

Fr



Melaka

MALAYSIA

getview vol 4 no 4 july 2014

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