双掺粉煤灰再生骨料对混凝土强度影响研究

通过试验研究再生骨料混凝土中粉煤灰和再生骨料对混凝土强度的影响。采用粉煤灰替代部分水泥、再生骨料替代部分天然粗骨料的方法,通过正交试验测定混凝土立方体抗压强度的方法,来研究粉煤灰对再生骨料混凝土强度的影响。试验得出:当再生骨料掺量为20%~30%时,粉煤灰的最佳掺量为20%左右;当再生骨料掺量高于40%、粉煤灰掺量高于20%时,其混凝土拌合物搅拌时间不小于240 s,且当粉煤灰在20%~30%时,可获得较理想的混凝土抗压强度;当粉煤灰的掺入量分布在20%~30%、再生骨料的最佳掺量为50%时,可获得较理想的混凝土抗压强度。由此得出,合理的再生骨料、粉煤灰掺量对混凝土的抗压强度影响并不明显且有提高的趋势,对降低混凝土成本,提高建筑垃圾的再生利用,有一定的经济效益和社会效益。

Study on the effect of recycled aggregate with double fly ash on the strength of concrete

Through experiments,this project studies the influence of a certain amount of fly ash on the strength of recycled aggregate concrete,so as to determine the optimal amount of fly ash in recycled aggregate concrete and reduce the adverse effect of hydration heat of cement in mass concrete construction.At the same time,the amount of cement can be reduced to reduce the cost of concrete.The influence of fly ash on the strength of recycled aggregate concrete was studied by using the method of replacing part of cement with fly ash(the content of fly ash is from 15%to 30%)and replacing part of natural coarse aggregate with recycled aggregate(the content of recycled aggregate is from 20%to 50%)and determining the compressive strength of concrete cube through orthogonal experiment.When the recycled aggregate content is 20%~30%,the optimal content of fly ash is about 20%.When the recycled aggregate content is more than 40%and the fly ash content is more than 20%,the mixing time of concrete mixture is no less than 240 s,and when the fly ash content is 20%~30%,the ideal compressive strength of concrete can be obtained.When the fly ash content is distributed in 20%~30%,the best content of recycled aggregate is 50%.It can be concluded that the reasonable amount of recycled aggregate and fly ash has no obvious influence on the compressive strength of concrete and tends to increase,which has certain economic and social benefits to reduce the cost of concrete and improve the recycling of construction waste.