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Sustainable construction is highlighted in current development as the environmental issue is one of the major issues of global concern. This issue also relates to waste generated each year. The bulk of waste was estimated to increase, which can reduce space in the world and can cause pollution. Many researchers have come up with inventions and ideas to manage that situation. Some researchers use the waste rubber in a concrete mix as a partial coarse or fine aggregate replacement. The alternative in a concrete mix depends on the size of the rubber that is used and the appropriateness. In this paper, the critical perspective of waste rubbers discussed in detail. It is shown from the review that if compared with the existing one, there is some reduction in the workability and mechanical properties of concrete. Rubberised concrete, however, still has its superiority in terms of energy absorption. The use of pozzolanic material in the concrete mix, the application, the proportion of rubber and the choice of rubber types helps a lot to compensate for the weakness of rubberised concrete.

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Behaviour of Reinforced Concrete (RC) in beam structure has captured attention of many researchers. Many past researchers investigated the issue of concrete strength in tensile zone. The present research investigates the effect of waste nylon cable ties fibre that act as an Artificial Plastic Fibres (APF) in normal concrete mix and RC beam element. The concrete strength of 30 MPa have been utilized in this research. The percentage of APF that has been mixed with the concrete paste are 1% and 3%. For strength performance, nine (9) cube specimens and nine (9) cylinder specimens were tested under compressive and splitting tensile test, respectively. In addition, six (6) RC beam specimens were prepared and tested under three points bending test in order to investigate its structural performance. Based on the results, 0%, 1% and 3% of APF in concrete mix produces tensile strength of 1.89 MPa, 3.37 MPa and 2.66 MPa respectively. While, from the compression tests, 50.9 MPa, 47.2 MPa and 24.5 MPa were generated from 0%, 1% and 3% of APF, respectively. From this observations, only 1% of APF was employed in concrete mix to produce RC beam for structural performance investigations. Based on three point bending test, RC beam that consisting 1% of APF produced maximum load about 35.98 kN with 1.8 mm deflection compared with control specimen that can only endured until 27.93 kN of maximum load with 2.37 mm deflection. Further observation reveals that cracking of RC beam consisting 1% of APF reduce and delay the crack formation. Overall, utilization of 1% APF in RC beam successfully improves its strength and structural performance.

Rubberized concrete was innovated by many researchers to enhance energy absorption under impact load and by reusing scrap tires. Thus, this research was aims to develop the numerical procedure using the Finite Element Method (FEM) to simulate modified rubberized concrete under impact loads and predict its energy absorption under different impact loads. Three existing constitutive models: Concrete Damage Plasticity (CDP), Drucker-Prager (DP), and Modified Drucker-Prager Cap (MDPC) available in ABAQUS software were used to replicate the rubberized concrete with 10% of Rice Hush Ash (RHA) as cement substitution and different percentages (0%, 5%, 10%, 15%, and 20%) of crumb rubber as sand replacement. All three models produced successful FEM results with reasonable modelling assumption, and the CDP model was more effective in simulating rubberized concrete under impact to predict energy absorption than DP and MDPC models. Further, it was concluded that crumb rubber could enhance the energy absorption of concrete. Generally, the energy absorption of the concrete increased as the crumb rubber increase. However, the strength decreased as the crumb rubber increased, but 10% of RHA in concrete mix can maintain the concrete strength. Overall, this study reveals that FEM incorporated with the CDP model is able to predict the impact response of modified crumb rubber as an application of concrete road barrier.