聚乙烯醇纤维沙漠砂混凝土配合比试验研究

Experimental Study on Mix Proportion of Polyvinyl Alcohol Fiber Reinforced Desert Sand Concrete

为充分发挥沙漠砂的颗粒填充优势和改善沙漠砂混凝土力学性能,本文基于Dinger-Funk紧密堆积理论开展了聚乙烯醇纤维沙漠砂混凝土配合比设计方法的试验研究。首先,应用Dinger-Funk紧密堆积理论得到优化砂率为42%,优化沙漠砂质量替代率为10%、20%和30%,混凝土骨料颗粒级配得到改善,混合细集料的细度模数从3.27分别降到2.92、2.81和2.71,有效孔隙率从2.50%分别降到1.65%、1.45%和1.51%;其次,采用正交试验方法,研究了水胶比、沙漠砂质量替代率、聚乙烯醇纤维体积掺量对混凝土和易性、抗压强度、劈裂抗拉强度和抗折强度的影响规律。结果表明,随沙漠砂质量替代率和纤维掺量的增加,混凝土拌合物和易性先提高后降低,抗压、劈裂抗拉和抗折强度均表现为先增大后减小的趋势。综合考虑和易性和力学性能试验结果,确定C30聚乙烯醇纤维沙漠砂混凝土最优配合比为水胶比0.45,沙漠砂质量替代率20%,聚乙烯醇纤维体积掺量0.10%。

In order to give full play to the particle filling advantage of desert sand and improve the mechanical properties of desert sand concrete,this paper carried out an experimental study on the mix proportion design method of polyvinyl alcohol fiber reinforced desert sand concrete based on Dinger-Funk close-packing theory.Firstly,applying the Dinger-Funk close-packing theory,the optimized sand rate is 42%,the optimized desert sand mass replacement ratio is 10%,20%and 30%,the concrete aggregate particle gradation is improved,the fineness modulus of mixed fine aggregate is reduced from 3.27 to 2.92,2.81 and 2.71,and the effective porosity is reduced from 2.50%to 1.65%,1.45%and 1.51%,respectively.Secondly,the orthogonal test method was used to study the effects of water-cement ratio,desert sand mass replacement ratio,and the volume dosage of polyvinyl alcohol fiber on the workability,compressive strength,splitting tensile strength and flexural strength of concrete.The results show that,with the increase of desert sand mass replacement ratio and fiber dosage,the workability of concrete firstly increase and then decrease,and the compressive strength,splitting tensile strength and flexural strength show the trend of firstly increasing and then decreasing.Considering the test results of the workability and mechanical properties,the optimal mix proportion of C30 polyvinyl alcohol fiber reinforced desert sand concrete is determined to be 0.45 water-cement ratio,20%of desert sand mass replacement ratio,and 0.10%of polyvinyl alcohol fiber volume dosage.