Engineering Behavior of Concrete with Recycled Aggregate

Concrete is extensively used as construction materials in Malaysia. Concrete contributes suitable feature for construction industry for instance durability, adequate compressive strength, fire resistance, availability and is economic as compared to other construction materials. Depletion of natural resources and disposal of construction and demolition waste remarkably claim environmental threat. In this paper, the engineering behavior, durability, and concrete microstructure of recycled concrete aggregates (RCA) on short-term concrete properties were investigated. The studied concrete at design mix proportion of 1:0.55:2.14:2.61 (weight of cement :coarse aggregates :sand :water) used to obtain medium-high compressive strength with 20%, 50%, and 100% of RCA. Results show that for the same water/cement ratio, RCA replacement up to 50% still achieved the targeted compressive strength of 25 MPa at 28 curing days. Addition, at similar RCA replacement, the highest carbonation depth value was found at 1.03 mm which could be attributed to the pozzolanic reaction, thus led to lower carbonation resistance. Scanning electron microscopy microstructure shows that the RCA surface was porous and covered with loose particles. Moreover, the interfacial transition zone was composed of numerous small pores, micro cracks, and fissures that surround the mortar matrix. On the basis of the obtained results, recommendable mineral admixtures of RCA are necessary to enhance the quality of concrete construction

Engineering Behavior of Concrete with Recycled Aggregate

Concrete is extensively used as construction materials in Malaysia. Concrete contributes suitable feature for construction industry for instance durability, adequate compressive strength, fire resistance, availability and is economic as compared to other construction materials. Depletion of natural resources and disposal of construction and demolition waste remarkably claim environmental threat. In this paper, the engineering behavior, durability, and concrete microstructure of recycled concrete aggregates (RCA) on short-term concrete properties were investigated. The studied concrete at design mix proportion of 1:0.55:2.14:2.61 (weight of cement :coarse aggregates :sand :water) used to obtain medium-high compressive strength with 20%, 50%, and 100% of RCA. Results show that for the same water/cement ratio, RCA replacement up to 50% still achieved the targeted compressive strength of 25 MPa at 28 curing days. Addition, at similar RCA replacement, the highest carbonation depth value was found at 1.03 mm which could be attributed to the pozzolanic reaction, thus led to lower carbonation resistance. Scanning electron microscopy microstructure shows that the RCA surface was porous and covered with loose particles. Moreover, the interfacial transition zone was composed of numerous small pores, micro cracks, and fissures that surround the mortar matrix. On the basis of the obtained results, recommendable mineral admixtures of RCA are necessary to enhance the quality of concrete construction

Effect of fiber loading on the flexural and tensile strength of oil palm frond fiber reinforced polymer composite

Research on composite have been widely done throughout the world. Incorporation of reinforcing materials into matrix can one day replace the use of conventional materials such as polymers, metals, ceramics and woods. In this research, a composite made of oil palm frond fiber and urea formaldehyde is fabricated. As oil palm frond fiber can be obtained in great amount due to high amount of wastage generated, composite can be a way to reduce this wastage. There are two different type of fiber loading which is 40% and 50%. The fiber and UF are mix until it is homogenous. It is then placed into the hot press machine to undergo hot press process. After the fabrication, the mechanical properties of the composite will be tested and observed. The mechanical test includes flexural and tensile test. Both tests are done in accordance to the ASTM standard which are ASTM D-790 and ASTM D-638. The morphological characteristic of the composite will also be observed in this study. The results show that the composite with higher fiber loading, which is 50 %, have better mechanical properties. The composite with 50 % of fiber has a flexural strength of 1.4306 MPa, a modulus of elasticity of 1248.9516 MPa and a tensile strength of 3.874 MPa. These composites can be used as an alternative for wood and automotive application