路用碾压混凝土稠度与配合比研究

Study on the consistency and mixture proportioning of roller compacted concrete for pavement

提出一种新的碾压混凝土配合比设计方法以同时获得其最大干密度及合适稠度。首先研究了骨料级配、含水量、砂率、水泥用量以及粉煤灰掺量对路用碾压混凝土稠度的影响，然后采用施压振动法确定碾压混凝土的干密度和含水率的关系，测试碾压混凝土的抗弯拉强度，最后综合确定碾压混凝土的配合比。研究结果表明：对于路用碾压混凝土，骨料级配、砂率及含水量是影响碾压混凝土稠度和压实度的主要因素。当骨料级配连续，混合料砂率为50％，水泥用量为骨料质量的15％，含水量约为所有干料质量的6％时，碾压混凝土改进的维勃时间（改进VC值）在工程要求的35-45S范围内，且压实度较大，所得到的抗弯拉强度能够满足农村公路的强度要求，因此采用的新方法是有效可行的。

Proposed a new mix design method to simultaneously obtain maximum dry density and suitable consistency of roller com- pacted concrete.Firstly, it investigated the influence of aggregate gradation, water content, fine aggregate ratio, cement content, and the content of fly ash on the consistency of roller compacted concrete （RCC） ; it established the relation between dry density and water con- tent based on the consolidated methods by vibration under a surcharge mass; finally, it tested the flexural strength and determined the final mixture proportion synthetically.The research results showed that aggregate gradation, fine aggregate ratio and water content were principle influencing factors of the consistency and the degree of compaction of RCC.When aggregate gradation was continuous, the fine-to-coarse aggregate ratio of the mixture was 50% by mass,the cement dosage was 15% of the aggregate mass,and the water content was 6% of the mass of the sum of all the dry ingredients, the modified vebe time （modified VC value） of RCC falls within the acceptable range of 35-45 s in engineering applications, and the RCC also exhibited high degree of compaction, and could achieve the flexure strength re- quired for the rural roads.Therefore, the new method is effective and feasible.