软弱砂岩骨料碾压混凝土的配制及其特性研究

Preparation and performance of roller compacted concrete with soft sandstone aggregate

在东南亚和我国西南地区由于缺乏合适的原材料,必须采用软弱骨料配制混凝土。以东南亚某工程现场的软弱砂岩为原材料,开展碾压混凝土配制和性能试验工作,探讨了该骨料配制碾压混凝土的可行性。采用软化系数为0.71的软弱砂岩,配制强度等级分别为C18020的二级配碾压混凝土和C1807.5的三级配碾压混凝土。结果表明,采用该砂岩骨料可以配制出满足强度要求的碾压混凝土,其用水量比常规骨料高15~20 kg/m3,拌和物密度和抗压弹模较低。其中,二级配碾压混凝土采用50％粉煤灰掺量、0.55水胶比；三级配碾压混凝土采用60％粉煤灰掺量、0.65水胶比。骨料抗碾压破碎模拟试验表明该骨料在碾压过程中破坏程度很低,说明采用该软弱骨料配制碾压混凝土具有可行性。

Soft aggregates have to be adopted to make concrete due to the lack of appropriate raw materials in the areas of Southeast Asia and Southwest China. A type of soft sandstone from a construction site in Southeast Asia was applied in the preparation and performance experiment of roller compacted concrete （ RCC ） , and the application feasibility of such a soft aggregate was also discussed. The sandstone whose softening coefficient is 0. 71 was adopted to prepare the C18020 2-graded RCC and the C1807. 5 3-graded RCC. Experimental results show that the strength of the RCC can meet the requirement of designing;the water usage is 15~20 kg/m3 higher than the RCC with normal aggregate, and the density and compressive elastic modulus are apparently lower. For the 2-graded RCC, the content proportion of fly ash is 50%, and the W/B ratio is 0. 55;and for the 3-graded RCC , the content proportion of fly ash is 60% and the W/B ratio is 0. 65. Since the soft aggregate was rarely damaged in the indoor broken-resistance experiments, the aggregate of soft sandstone is practicable for the preparation of RCC.