Oil palm empty fruit bunches (EFB) and silica fume (SF) are the by-products of the oil palm plantation and the ferroalloy smelting industries, respectively. Improper disposal of these materials leads to negative implication to the environment. This study was carried out to investigate the potential application of EFB and SF in cement bricks. EFB fibre and SF replaced up to 25% of sand and cement in the mix, respectively, in several groups of specimens that distinguished the normal, EFB-, SF- and EFB-SF-cement bricks. The specimens were tested for the compressive strength, density and water absorption property. The results reveal that SF, at an optimum amount of 10% cement replacement, increased 10% of the strength of the cement brick. EFB fibre reduced the strength and density but increased water absorption property of the cement brick. For application in the construction industry, SF and EFB fibre contents should be kept within 10% and 20% respectively.

This research aims to examine the chemical properties of waste rubber tyre granules. Rubber granules were analysed by using X-ray fluorescence to establish its chemical composition. Thermogravimetry and differential thermogravimetric analyses were performed to investigate the relationship between temperature and the minerological compositions of rubber granules to determine its suitability as an aggregate replacement in concrete mix. Fourier Transform Infra-Red (FTIR) indicated that due to the stability of the structures developed in OPC samples, the reactions between the structure bonds are less at the range of 650-1500 cm-1. Scanning electron microscopy (SEM) was performed to examine the physical properties of rubber granule particles and to magnify the bonds between cement and rubber granules in a concrete mix. The results of the SEM analysis showed that carbon, zinc, magnesium, and calcium are the major components of waste tyre rubber granules.

This paper aims to examine the effect of replacing the natural aggregate with waste tyrerubber granules. Waste tyrerubber granules were used as aggretate replacement in the pavingblock at four different percentage: 10%, 20%, 30%, and 40%. The paving blocks were tested in terms of their strength and the characteristics of their microstructure by measuring compressive strength, flexural strength, splitting tensile strength, and skid resistance. Field scanning electron microscopy (FESEM) and Fourier Transform Infra-Red(FTIR) analysis werecarried out on the paving block specimen. When 10% of the natural aggregate was replaced with waste tyrerubber granules, there was no substantial difference in the compressive strength but the flexural and splitting tensile strength increased to a certain extent. When more than 20% of waste tyrerubber granulesis incorporated in the paving blocks, the strength is acutely reduced even though there is a growth in ductility. The results proved that even after failure, the paving blocks did not shatter but still stayed imperforated. Double layer rubberized concrete paving blocks (DL-RCPBs) are more flexible and soft to the surface, and thus provide a better ride quality. This characteristic makes it suitable for trafficked roads. DL-RCPBs (30% and 40%) with low strength characteristics could be used on roads that not required high strength and may be viable for other applications, depending on the percentage of waste tyre rubber used. DL-RCPB with higher waste tyre rubber content exhibit higher skid resistance especially on dry surface but reduced on slippery surface. Two main factors that influence the skid resistance are high elasticity and rough surface texture of waste tyre rubber. It is suggested that DL-RCPBs could be introduced as one of alternative concrete paving block (CPB) that can be used in paving application.

This paper presents a study on the investigation of waste tyre rubber (rubber granule) as aggregate in the production of concrete paving block (CPB) with double layers. A series of tests were carried out to determine the properties of double layer rubberized concrete paving blocks (DL-RCPB). In this study, there are four series of concrete mix with 10 %, 20 %, 30 % and 40 % of waste tyre rubber replacement level. The dimension of CPB was 200 mm x 100 mm x 80 mm with 20 mm thickness of facing layer. The results showed that the percentage of waste tyre rubber content for DL-RCPB affects the density, porosity and compressive strength. The control concrete paving block (CCPB) and DL-RCPB (10 %) achieve the minimum strength requirement of 45 MPa. The density of DL-RCPB (40 %) recorded reduce 24 % as compared to CCPB. At 28 days, the percentage of porosity increased up to 55 % when 40 % of aggregate were replaced with rubber granule. The skid resistance of concrete block increased by 7 % with the incorporation of rubber granule particle size of 1 – 4 mm and 5 – 8 mm up to 40 % as the replacement of fine aggregate and coarse aggregate, respectively.

This study provided the test results on the mechanical properties of double layer concrete paving blocks (CPBs) obtained by replacing portions of the conventional aggregate with waste tyre rubber. The mechanical properties discussed in this paper were compressive and flexural strength. Results indicated that the density of double layer CPBs containing rubber was lower than that of conventional CPB. The decrease was found to be proportional with the waste tyre rubber content. Due to the low strength and stiffness of waste tyre rubber particle, the compressive and flexural strength of double layer CPBs containing rubber appeared to be lower than that of conventional CPB.