ABSTRACT:The performance of concrete made from recycled aggregate that produced by pulsed power technology due to the use of fly ash has been studied. Pulsed power technology has been proven to reproduce high quality recycled aggregate. Concrete made from 100% recycled coarse aggregate by pulsed power discharge can reach similar compressive strength to natural coarse aggregate concrete. The use of JIS type II fly ash as cement replacement of 25% and 50% mass without adjustment of water to cement ratio can reduce the compressive strength of concrete. However, with the same fly ash percentage, in 28 day of age, concrete made from recycled aggregate by pulsed power technology results better strength by 10.0% and 15.8% compared to natural aggregate concrete for 25% and 50% of fly ash, respectively. In addition, mixing method using two-stage mixing approach (TSMA) has been applied to improve concrete strength. This method in making recycled aggregate concrete can improve the strength of fly ash concrete made from recycled aggregate concrete up to 4.7%. Replacing 25% of cement mass with fly ash for concrete made from recycled aggregate by pulsed power technology has shown preferable result in strength, and can be improved by using TSMA method in mixing process.

Early age compressive strength, porosity, and sorptivity of concrete using peat water to produce and cure concrete AIP Conference Proceedings 1887, 020027 (2017) Abstract. The performance of porous concrete made of recycled coarse aggregate was investigated. Fly ash was used as cement partial replacement. In this study, the strength of recycled aggregate was coMPared to low quality natural coarse aggregate which has high water absorption. Compression strength and tensile splitting strength test were conducted to evaluate the performance of porous concrete using fly ash as cement replacement. Results have shown that the utilization of recycled coarse aggregate up to 75% to replace low quality natural coarse aggregate with high water absorption increases compressive strength and splitting tensile strength of porous concrete. Using fly ash up to 25% as cement replacement improves compressive strength and splitting tensile strength of porous concrete.

Pervious concrete is a type of pavement made with minimal fine aggregate and high void ratio that allows stormwater to infiltrate into the soil and overcomes surface runoff problems. In this paper, the utilization of fly ash as supplementary cementitious material to the mechanical properties of pervious concrete made with recycled aggregate was investigated. Recycled aggregate was reclaimed from concrete waste to make pervious concrete. 0%, 50%, and 100% of recycled aggregate were used to replace natural coarse aggregate; while 0%, 15% and 25% of fly ash were used as cement replacement. The mechanical properties of pervious concrete were evaluated by determining the compressive strength, splitting tensile strength and flexural strength at 28 days. The results revealed that the use of recycled aggregate significantly affected the strength of pervious concrete. Further, the experimental results show that fly ash as supplementary cementitious material improved the compressive strength, splitting tensile strength and flexural strength of pervious concrete.

The use of concrete waste from the demolition of buildings is one of the conservation efforts to reduce its environmental impact. In this study, concrete waste was destroyed by the size of coarse aggregates, then made into porous concrete. Porous concrete from recycled coarse aggregate was used as filtration media to reduce the pollutants in wastewater to satisfy the water quality standards. For this purpose, wastewater from the communal wastewater treatment plant was filtrated through two layers of porous concrete made of recycled coarse aggregate with several different sizes, and the water quality output of the system was measured according to water quality parameter standard. The objective of this study is to examine the effectiveness of the aggregate sizes of normal coarse aggregate compared to recycled coarse aggregate as filtration media. From the result of the water treatment filtration model, it was found that the size of coarse aggregate in the porous concrete mix has a significant effect for reducing the water pollutants, as biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS). As a result of this study, porous concrete made from recycled coarse aggregate shows better performance on filtrating the water pollutants.

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