基于响应曲面法的水库底泥泡沫混凝土配合比优化研究

Optimization of mix ratio of reservoir sediment foamed concrete based on response surface method

摘要

【目的】为了提高水库底泥的高值化利用率，拟使用水库底泥来制备泡沫混凝土，以水胶比、底泥掺量、泡沫掺量为变量【方法】采用Design-Expert 13.0软件中响应曲面法对水库底泥泡沫混凝土的配合比进行优化设计，分析变量对水库底泥泡沫混凝土抗压强度和导热系数的影响。采用SEM和XRD探究了底泥泡沫混凝土微观结构。【结果】研究结果显示，对水库底泥泡沫混凝土28 d抗压强度影响顺序为：水胶比>泡沫掺量>底泥掺量，而导热系数的影响顺序为：水胶比>底泥掺量>泡沫掺量。随着水胶比增加，抗压强度先升高后下降，导热系数逐渐降低。增加泡沫和底泥掺量会导致抗压强度和导热系数均下降。孔隙率与导热系数呈现负相关，符合指数模型。【结论】经优化配比，水库底泥泡沫混凝土在水胶比0.4、底泥掺量30%、泡沫掺量4.2%条件下制备，其28 d抗压强度为18.19 MPa,导热系数为0.121 4W/(m·K),表观密度为701.2 kg/m³。微观结果分析表明，底泥掺入量为30%条件下，试块内部物相结合紧密，孔隙分布均匀。研究成果为水库底泥在建筑材料领域的利用提供了新途径。

Abstract

[Objective] To improve the high-value utilization of reservoir sediment, reservoir sediment foamed concrete was prepared by taking the water binder ratio, reservoir sediment mixing amount and foam mixing amount as variables. [Methods] The response surface method in the Design-Expert 13.0 software was used to optimize the mix ratio design, analyze the effects of variables on the compressive strength and thermal conductivity of the reservoir sediment foamed concrete. SEM and XRD were used to explore the microstructure of the reservoir sediment foamed concrete. [Results] The results show that the influence of each factor on the 28 d compressive strength of reservoir sediment foamed concrete is in the following order: water binder ratio>foam content >reservoir sediment content, and the thermal conductivity is in the following order: water binder ratio> reservoir sediment content >foam content. With the increase of water binder ratio, the compressive strength increases at first and then decreases, and the thermal conductivity gradually decreases. Increasing foam and reservoir sediment mixing result in a decrease in both compressive strength and thermal conductivity. Porosity showed a negative correlation with thermal conductivity, consistent with an exponential model. [Conclusion] The optimal mix ratio of reservoir sediment foamed concrete is 0.4, 30% of reservoir sediment and 4.2% of foam content, and the 28 d compressive strength of the foamed concrete is 18.19 MPa, and the thermal conductivity is 0.121 4 W/(m·K), apparent density is 701.2 kg/m³. The analysis of microscopic result showed that the internal material of the specimen was tightly bound and the pores were uniformly distributed under the condition that the amount of reservoir sediment was 30%. Reservoir sediment foamed concrete provide a new way for the use of reservoir sediment in the field of construction materials.

关键词

水库底泥 / 泡沫混凝土 / 响应曲面法 / 抗压强度 / 导热系数 / 影响因素 / 水胶比 / SEM图

Key words

reservoir sediment / foamed concrete / response surface method / compressive strength / thermal conductivity / influencing factors / water cement ratio / SEM image

基金资助

国家自然科学基金项目(52278171)

河北省自然科学基金项目(E2020402079)

河北工程大学大学生创新创业训练计划项目(X202410076013)