摘要
机制砂含泥引起的混凝土性能劣化问题是混凝土行业亟待解决的难题。采用硅基防水剂、黏土防膨剂作为双组分表面改性剂对机制砂进行表面预处理,降低机制砂中泥粉含量对混凝土工作性能的负面影响。探究改性剂的种类和用量对机制砂吸水率与亚甲蓝值(MB值)的影响以及与减水剂吸附量、黏土层间距之间的关系,还高效研究表面改性处理工艺对胶砂流变行为以及混凝土工作性能、力学性能和耐久性能的影响。研究结果表明:双组分改性剂中防水剂与防膨剂的最佳质量比为6∶4,最优用量为机制砂质量的1.5‰。表面处理后机制砂的吸水率降低42.3%,MB值从3.2下降至1.5,混凝土减水剂掺量可降低5.7%~14.3%,1.5 h扩展度增大70~120 mm,同时降低了泥粉对混凝土力学性能和耐久性能的负面影响,减小了机制砂含泥量变化和黏土杂质种类差异引起的工作性能波动。
The deterioration of concrete performance caused by manufactured sand with clay has become an urgent problem to be solved in concrete industry.Silicon-based waterproofing agent and clay anti-swelling agent were used as the two-component surface modifier.The modifier was applied to pretreat the surface of manufactured sand,which can improve the working performance of concrete with clay.The effects of the type and amount of modifier on the water absorption and methylene blue value(MB value)of manufactured sand,as well as the relationship with the adsorption amount of superplasticizer and the spacing between clay layers were investigated.The influence of surface modification treatment on the rheological behavior of mortar,the working performance,mechanical performance and durability of concrete was studied.For the two-component modifier,the optimal mass ratio of water-proofing agent and anti-swelling agent was 6∶4,and the optimal dosage was 1.5‰of the quality of the manufactured sand.After surface treatment,the water absorption of manufactured sand was reduced by 42.3%and MB value decreased from 3.2 to 1.5.The dosage of superplasticizer can be reduced by 5.7%-14.3%,and the slump flow of 1.5 h can be increased by 70-120 mm.The results show that the surface modification technology can improve the fluidity and retention of the concrete and enhance the mechanical perfor-mance and durability of the concrete,and also reduce the fluctuation of concrete working performance caused by the variation of clay content and clay species.
作者
高育欣
刘明
曾超
王福涛
王鹏
叶子
张磊
GAO Yuxin;LIU Ming;ZENG Chao;WANG Futao;WANG Peng;YE Zi;ZHANG Lei(China West Construction Academy of Building Materials Co.,Ltd.,Chengdu 610052,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第22期22072-22078,22084,共8页
Materials Reports
关键词
表面改性
机制砂
黏土
混凝土
工作性能
surface modification
manufactured sand
clay
concrete
working performance
