水泥基采石场粉尘泡沫轻质土力学性能及微观机理研究

Study on Mechanical Properties and Microscopic Mechanism of Dust Foam Lightweight Soil in Cement-Based Quarries

摘要: 为了研究水泥基采石场粉尘泡沫轻质土的力学性能和微观机理，以水泥、采石场粉尘作为胶凝材料制作泡沫轻质土，分析湿密度(500 kg/m³、600 kg/m³、700 kg/m³、800 kg/m³)、采石场粉尘掺量(0%、7.5%、12.5%、17.5%、22.5%)及标准养护龄期(3 d、7 d、14 d、28 d)等因素对泡沫轻质土的流值、无侧限抗压强度、孔泡结构的影响，建立强度预测模型。结果表明：流值随采石场粉尘掺量先减小后增大，与设计湿密度成正比；采石场粉尘掺量低于12.5%时，能有效提高无侧限抗压强度；相同养护龄期内，设计湿密度与抗压强度成正比；分析了抗压强度微观机理，湿密度越大，泡沫轻质土孔隙率越低；采石场粉尘掺量越多，平均孔径越小；依据实验结果，建立了适用于不同配合比的水泥基采石场粉尘泡沫轻质土的无侧限抗压强度预测公式。研究成果可以为该材料的工程应用提供依据。

Abstract: In order to study the mechanical properties and microscopic mechanism of cement-based quarry dust foam lightweight soil, cement and quarry dust were used as cementitious materials to make foam lightweight soil, and the effects of wet density (500 kg/m³, 600 kg/m³, 700 kg/m³, 800 kg/m³), quarry dust content (0%, 7.5%, 12.5%, 17.5%, 22.5%) and standard curing age (3 d, 7 d, 14 d, 28 d) on the flow value, unconfined compressive strength and pore structure of foam lightweight soil were analyzed, and a strength prediction model was established. The results show that the flow value decreases first and then increases with the dust content of the quarry, which is proportional to the design wet density. When the dust content of the quarry is less than 12.5%, the unconfined compressive strength can be effectively improved. During the same curing period, the design wet density is proportional to the compressive strength. The microscopic mechanism of compressive strength was explained, and the higher the wet density, the lower the porosity of foam lightweight soil. The higher the amount of dust in the quarry, the smaller the average pore size. According to the experimental results, a prediction formula for the unconfined compressive strength of cement-based quarry dust foam lightweight soil with different mix ratios was established. The research results can provide a basis for the engineering application of this material.