PSI - Issue 47
Noorsuhada Md Nor et al. / Procedia Structural Integrity 47 (2023) 732–743 Author name / Structural Integrity Procedia 00 (2019) 000–000
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influence their structural performance, with certain shapes exhibiting different strength and durability. For example, Rathan and Sunitha (2022) investigated the effective modulus of elasticity for the face layer in the construction of concrete block pavers with different block shapes. The test results showed that the zigzag block shape is the better one compared to the other shapes as it reduces the deflection values. The difference in the modulus of elasticity of the zigzag and rectangular blocks was found to be 48.21 MPa. This is due to the interlocking on all sides of the block compared to I-shaped blocks with two interlocked sides and rectangular blocks without interlocking on the sides. Since shape plays an important role in the production of concrete blocks, two types of concrete blocks were produced in this study: a solid concrete block and a one hollow interlocking concrete block. The main purpose of this study is to determine the behaviour of solid and one hollow concrete block made of RCA under flexural load. 2. Methodology 2.1. Preparation of materials RCA, natural fine aggregate (sand), ordinary Portland cement, water and superplasticizer in different proportions were used for the production of interlocking concrete blocks. The aggregate used in this study consisted of 50% each of RCA and natural fine aggregate. The RCA was made from the tested cubes collected from the MDC plantation site. The tested cubes had a strength in the range of 25-30 MPa, which was used for house construction. The tested cubes were first crushed using a hacker to produce small particles. The RCA was then crushed into small fragments using a jaw crusher. These fragments were sieved to sort out oversized material and then sorted by particle size distribution through sieve analysis. The resulting recycled concrete aggregate (RCA) was limited to a maximum size of 5 mm, and all RCA that passed this sieve was used to make interlocking concrete blocks. Fig. 1 shows the gradation of the RCA and sand. The ordinary Portland cement has a specific gravity of 3.15 g/cm³. A water-cement ratio of 0.65 was used to produce the concrete mix.
Sand
RCA
100 120
0 20 40 60 80
Percentage Passing
0.01
0.10
1.00
10.00
Sieve Size (mm)
Fig. 1. Particle size distribution for sand and RCA
2.2. Preparation of cubes interlocking concrete block The cubes and interlocking concrete blocks were made from the cement mortar consisting of cement, RCA, sand and water mixed in a ratio of 1:4 for cement: aggregate as illustrated in Fig. 2. The aggregate consists of 50% RCA and 50% sand. To mix the cement mortar, all materials were weighed and measured. Then all materials were mixed thoroughly until the mixture was smooth and uniform and no longer contained any dry pockets of cement or sand. The superplasticiser was added to the mixture in the amount of 1% of the cement weight.
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