Concrete, which is made of cement, fine and coarse aggregates and water, is the most used building material in the world. It's durable, strength and ease of availability have been its main advantages. Concrete is strong in compression while it is known to be weak in tensile. Over the years different methods and materials have been utilized to reinforce concrete to overcome such weakness. Fibre reinforcement has shown considerable improvement in the properties of concrete. Therefore, in this study, M20 grade concrete was reinforced with steel fibres which were added at a volume fraction of 1%, 2%, 3%, 4% and 5% and compared with a control sample with no steel fibres. The effect on the workability of concrete with the steel fibre reinforcement was determined as well as the effect on flexural and compressive strengths concrete. Based on the results, the reinforcement of steel fibres had a significant adverse impact on the workability, with the increase in fibre content, the workability decreased. On the other hand, a significant enhancement was observed in the mechanical properties of concrete with the addition of steel fibres, achieving higher strength than the control sample. The highest compressive and flexural strength was gained with the addition of 3%, a further increase in fibre content decreased the strength. Therefore, the optimum dosage of steel fibres was determined to be 3%. Although the compressive and flexural strengths are still higher at 5% reinforcement compared to controlled sample.

Concrete which is widely used material in the construction industry, has a carbon footprint. Approximately 10% of global Carbon Dioxide (CO2) gas is emitted during the production of cement which is vital ingredient of concrete. The increase in production of cement affects global warming and climate change. Therefore, many have attempts have been made to develop green and sustainable concrete by utilizing different waste materials. With the utilization of waste materials as cement replacement, the CO2 gas emissions can be reduced as well as resolve the environmental issues that the inhabitants face during the disposal of such waste materials. This paper reviews the potential and innovative utilization of Rice Husk Ash (RHA) and Eggshells as partial cement replacement to develop green concrete. RHA which is rich in silica and eggshells contain identical amount of calcium oxide as cement, when finely grinded and used together as partial cement replacement, can trigger a pozzolanic reaction, in which silica reacts with calcium oxide resulting in the formation of calcium silicates which are responsible for achieving higher strengths.

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Malaysia faces three major environmental problems, out of which solid waste and management is one of them. Palm Oil Fuel Ash (POFA) and eggshells are two agro-food waste materials which are produced in enormous quantities in Malaysia. Due to the characteristics possessed by eggshells and POFA, these waste materials can potentially be utilized in the production as cement replacement, reducing the use of cement which is one of the major production of Carbon Dioxide (CO2) gas emissions. This study was conducted to determine the chemical and fresh state properties of foamed concrete incorporating POFA and eggshell ash (ESA) as cement replacement. Based upon the results, it was observed that the increase in usage amount of POFA and ESA as cement replacement, the workability of foamed concrete reduced without blocking. For the chemical analysis result shows the POFA which had high amount of silicon dioxide and ESA having large amount of calcium oxide were compatible and could be used together as cement replacement. The use of ESA and POFA as cement replacement to reduce the cement consumption with various percentage of ESA (0% - 15%) and POFA (20% - 35%) in 1800 kg/m3 density of foamed concrete.