粉煤灰制备轻质高强混凝土的试验研究

以烧结粉煤灰陶粒作为粗骨料,复掺超细粉煤灰与一级粉煤灰部分替代水泥作为胶凝材料,制备轻质高强混凝土.主要研究了两种粉煤灰的掺配比例与总掺量对轻骨料混凝土力学性能、干表观密度及微观形貌的影响.试验结果表明:掺超细粉煤灰能够细化水泥水化产物的晶体尺寸,打乱氢氧化钙的生长取向,减少混凝土内部结构缺陷,使胶凝材料浆体更均匀;当超细粉煤灰与一级粉煤灰的比例为1:1,粉煤灰的总掺量为40%时,可以配制出28 d抗压强度为58.6 MPa,干表观密度为1900 kg/m3的LC50轻质高强轻骨料混凝土.

Experimental Study on Preparing Lightweight& High Strength Concrete with Fly Ash

Lightweight and high strength concrete was prepared by using sintered fly ash ceramsites as coarse aggregates , partially substituting cement with ultra-fine fly ash and the first grade original fly ash . The effects of the blending ratio of two kinds of fly ashes and the total content of fly ash on the mechanics performance , dry apparent density and the microstructure of concrete were investigated .The results show that the addition of ultra-fine fly ash can refine the crystal size of the cement hydration product , upset the growth orientation of calcium hydroxide and reduce the internal structure defects of concrete , which makes the paste more uniform .When the blending ratio of the ultra-fine fly ash to the first grade original fly ash is 1:1 , and the total content of fly ash is 40%, the LC50 grade lightweight and high strength concrete, with the compressive strength of 58.6 MPa at 28 d and the dry apparent density of 1900 kg/m3 , is prepared .