Influence of temperature and chemical solution on removal mortar adhenred on recycled coarse aggregate in concrete

Abstract

In this research, recycled coarse aggregate from concrete waste is used in mix proportion in range from 25, 50, 75 and 100% by weight Recycled coarse aggregates are investigated in diameter 5 – 10 mm and 10 – 20 mm, repsectively. Hence, the temperature is investigated in range of 80, 100, 120 and 140⁰C. Chemical solution with concertration in range from 0.05 to 0.2 Mol/l is mixed. The results are indicated that concrete is tend to decreased in slump and strength with an increase in recycled coarse aggregate in mix proportion.  Besides, the affect of recycled coarse aggregate with 5 – 10 mm is more significantly than its with 10 – 20 mm in concrete. The adhered mortar in surface of recycled coarse aggregate can be reduced 4 – 5% with an increase in temperature in range from 80 to 140⁰C. Concrete can be improved in slump and strength with temperature up to 140⁰C for recycled coars aggregate 10 – 20 mm. Chemical solution can be used to treat coarse aggregate to reduce 15 – 20% in adhenred mortar with concertration 0,2 Mol/l. Thus, concrete can be significantly  improved in slump and strength by chemical solution. Strength can be increased up to 15 – 20% and 30% in group 5-10 mm and 10-20 mm, respectively. The workability and properties of concrete can be improved by chemical treatment with HCl solution.