煤矸石机制砂与风积砂混合砂浆的力学性能及微观机理

硅酸盐通报 ›› 2024, Vol. 43 ›› Issue (12): 4424-4433.

煤矸石机制砂与风积砂混合砂浆的力学性能及微观机理

邱继生¹, 牛高辉¹, 李蕾蕾², 冯泽平², 李乐¹

1.西安科技大学建筑与土木工程学院, 西安 710054;
2.中国电建集团西北勘测设计研究院有限公司, 西安 710065

收稿日期:2024-07-04 修订日期:2024-08-07 出版日期:2024-12-15 发布日期:2024-12-19
通信作者: 牛高辉,硕士研究生。E-mail:1102442657@qq.com
作者简介:邱继生(1977—),男,博士,副教授。主要从事固体废弃物综合利用的研究。E-mail:qiujisheng@xust.edu.cn
基金资助:
陕西省自然科学基金面上项目(2018JM5167)

Mechanical Properties and Microscopic Mechanism of Mixed Mortar with Gangue Machine-Made Sand and Eolian Sand

QIU Jisheng¹, NIU Gaohui¹, LI Leilei², FENG Zeping², LI Le¹

1. School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China;
2. China Electric Power Construction Group Northwest Survey and Design Institute Co.,Ltd., Xi’an 710065, China

Received:2024-07-04 Revised:2024-08-07 Published:2024-12-15 Online:2024-12-19

摘要/Abstract

摘要： 混合砂浆是利用煤矸石机制砂与风积砂按照不同比例(等质量)混合为混合砂并全部替代河砂配制出的一种新型砂浆。为探讨混合砂浆基本力学性能变化规律及微观机理,采用毛乌素沙漠风积砂与大柳塔煤矿产煤矸石机制砂配制混合砂浆试件,探究了混合砂浆抗压强度随两种砂复掺比例、混合砂浆养护龄期、混合砂细度模数的变化规律,揭示了强度变化规律的内在机理。结果表明:随着风积砂掺量的提高,混合砂浆强度先增大后减小,煤矸石机制砂与风积砂最优掺和比例为6 ∶4(质量比);混合砂浆抗压强度与混合砂细度模数之间满足二次函数关系,当混合砂细度模数为2.20时,混合砂浆力学性能最优;混合砂不同粒径颗粒间相互填隙,减小了砂浆内部孔隙,适量风积砂的掺入可使砂浆内滞留的大气泡分散成小气泡,改善砂浆结构;提出有益孔及有害孔的概念,从孔结构参数出发,解释了砂浆力学强度的变化规律,表明砂浆抗压强度变化是其内部孔隙率及孔径分布范围共同作用的结果;适量的风积砂与煤矸石机制砂混合有利于水化反应的进行,对结构有“补偿作用”,但随着风积砂掺量进一步提高,由于风积砂本身材料的缺陷,这种“补偿作用”无法弥补材料自身的缺陷。

关键词: 混合砂浆, 抗压强度, 微观机理, 孔隙结构, 有害孔, 补偿作用

Abstract: Mixed mortar is a new type of mortar that is prepared by using gangue machine-made sand and eolian sand to replace river sand in different proportion (equal mass). To explore the change rule and microscopic mechanism of the basic mechanical properties of mixed mortar, the mixed mortar specimens were prepared with the eolian sand of Mu Us Desert and the gangue machine-made sand of the Daliuta Coal Mine. The compressive strength change rules of mixed mortar with the two kinds of sand mixed ratio, curing age, and mixed sand fineness modulus were studied, and the internal mechanism of the strength change rule was revealed. The results show that with the increase of the proportion of eolian sand, the strength of mixed mortar increases first and then decreases, and the optimal mixing ratio of gangue machine-made sand and eolian sand is 6 ∶4 (mass ratio). The compressive strength of mixed mortar and the fineness modulus of mixed sand satisfy the quadratic function relationship. When the fineness modulus of mixed sand is 2.20, the mechanical properties of mortar are the best. The particles of different particle sizes of mixed sand fill each other, which reduces the internal pores of the mortar. The addition of an appropriate amount of eolian sand can disperse the large bubbles retained in the mortar into tiny bubbles and improve the structure of the mortar. The concepts of beneficial pore and harmful pore are proposed. Based on the pore structure parameters, the change process of mechanical strength of mortar is explained, which shows that the compressive strength of mortar is the result of the combined action of its internal porosity and pore size distribution range. The appropriate amount of aeolian sand mixed with gangue machine-made sand is conducive to the hydration reaction, which has a “compensation effect” on the structure. However, with the further increase of aeolian sand content, due to the defects of aeolian sand itself, this “compensation effect” cannot make up for the defects of the material itself.

Key words: mixed mortar, compressive strength, microscopic mechanism, pore structure, harmful pore, compensation effect action

中图分类号:

TU528

邱继生, 牛高辉, 李蕾蕾, 冯泽平, 李乐. 煤矸石机制砂与风积砂混合砂浆的力学性能及微观机理[J]. 硅酸盐通报, 2024, 43(12): 4424-4433.

QIU Jisheng, NIU Gaohui, LI Leilei, FENG Zeping, LI Le. Mechanical Properties and Microscopic Mechanism of Mixed Mortar with Gangue Machine-Made Sand and Eolian Sand[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(12): 4424-4433.

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