胶凝砂砾石材料抗冻性研究及配合比优化设计

Research on Freeze Resistance of Cemented Sand and Gravel Material Based on Response Surface Methodology and Optimal Design of Mixture Ratio

为提升寒区胶凝砂砾石材料的耐久性,对影响胶凝砂砾石材料抗冻性的因素进行综合优化分析。基于正交试验原理,利用Design-Expert软件,设计了以水胶比、砂率和粉煤灰掺量为因素,以质量损失率、相对动弹性模量为冻融试验响应指标的三因素三水平试验,通过构建响应面模型、等值线图及多目标优化设计进行研究分析。结果表明:建立的响应面回归模型较为精确,基于该模型利用渴求函数可以实现抗冻性能的多目标优化;影响胶凝砂砾石冻融后质量损失率的主要因素是水胶比和粉煤灰掺量,影响相对动弹性模量的主要因素是水胶比和砂率;结合渴求函数对胶凝砂砾石配合比进行多目标优化设计,得出最优砂率为0.2,粉煤灰掺量为30、40、50 kg/m^(3)时对应的最优水胶比分别为1.06、1.04、1.01。

In order to improve the durability of cemented sand and gravel materials in cold areas, a comprehensive optimization analysis of the factors affecting the frost resistance of cemented sand and gravel materials was carried out. Based on the principle of orthogonal experiment and using Design-Expert software, a three-factor and three-level test was designed with water-binder ratio, sand ratio and fly ash content as factors, and mass loss rate and relative dynamic elastic modulus as freeze-thaw test response indicators. Research and analysis were carried out by building response surface models, contour maps and multi-objective optimization. The results show that a more accurate regression model can be established based on the response surface and multi-objective optimization of frost resistance can be achieved by using the craving function based on this model;the significant factors affecting the mass loss rate of cemented sand and gravel after freezing are water-binder ratio and fly ash content;the significant factors affecting the relative dynamic elastic modulus are water-binder ratio and sand ratio;multi-objective optimization design for cemented sand and gravel mixing ratio combined with the desire function and the optimal sand ratio is obtained 0.2, when the optimal water-binder ratio is 1.06, 1.04 and 1.01, the corresponding fly ash content is 30, 40 and 50 kg/m^(3)respectively.