高泥粉石粉含量山砂制备低强高性能混凝土及其优化研究

Preparation of low strength and high performance concrete from mountain sand with high content of mud powder and stone powder and its optimization research

研究一种用于高原山区公路的MB值1.6 g/kg和石粉含量8.8%的高含泥含粉山砂低强高性能混凝土的制备及工作性、力学性能的影响。试验结果表明,适度增加山砂混凝土中水泥用量、粉煤灰掺量、砂率、减水剂掺量能有效改善其工作性能和提升混凝土的强度;其中水泥用量和粉煤灰掺量对山砂混凝土的强度影响比较明显,减水剂掺量和水泥用量对山砂混凝土的坍落度影响最为显著。结合正交试验,该山砂C30低强高性能混凝土材料最佳用量为:水泥、粉煤灰、山砂、碎石、水、减水剂分别为312、55、824、1049、156、3.67 kg/m^(3),制备的混凝土具有较好的抗渗性、抗冻性、收缩、抗碳化等耐久性能。

The preparation of a high-performance low-strength concrete with a MB value of 1.6 g/kg and a stone powder content of 8.8%with high silt-containing silt sand and high-performance low-strength concrete for highways in plateau and mountainous areas,and its influence on workability and mechanical properties were studied.The test results show that moderately increasing the cement,fly ash,sand ratio,and water reducing agent in the mountain sand concrete can effectively improve its working performance and enhance the strength of the concrete;among them,the amount of cement and fly ash content affects the strength of the mountain sand concrete obviously,the amount of water-reducing agent and the amount of cement have the most significant impact on the slump of mountain sand concrete.The best dosage of the mountain sand C30 low-strength high-performance concrete material is:cement,fly ash,mountain sand,crushed stone,water,water reducing agent=312、55、824、1049、156、3.67 kg/m^(3),the prepared concrete has good durability properties such as impermeability,frost resistance,shrinkage,and carbonization resistance.