外加剂掺量对煤矸石喷射混凝土力学性能和抗渗性的影响

doi:10.16552/j.cnki.issn1001-1625.2024.1563

摘要/Abstract

摘要： 煤矸石喷射混凝土(CGS)作为一种环保建筑材料,其性能受外加剂种类和掺量的显著影响,其中速凝剂和减水剂因具有良好的改性效果而得到广泛应用。本文基于单因素变量试验研究了不同掺量的速凝剂和减水剂对CGS力学性能和抗渗性的影响,确定了最优掺量,并通过回弹率和大板喷射试验进行验证,结果表明:减水剂的掺入使得CGS在1、7、28 d龄期下的抗压、劈裂抗拉强度呈先上升后下降再上升再下降的趋势,当减水剂掺量为2.50%(质量分数)时,各性能均达到最佳,试块无渗透现象,密实度良好;当速凝剂掺量为0%~3%(质量分数)时,CGS在1 d龄期抗压强度及劈裂抗拉强度略有提升,在7、28 d龄期的强度均逐渐降低,当速凝剂掺量为3%~12%(质量分数)时,各龄期的强度均显著下降;过量速凝剂(12%)显著加剧了CGS的渗透性,速凝剂掺量为3%时,CGS仅顶部出现渗透;回弹率试验显示,速凝剂与减水剂的协同作用改善了CGS流动性和黏结性,将回弹率降至13.03%;大板喷射试验表明,优化配比后的CGS抗压强度和劈裂抗拉强度较普通CGS显著提升,平均渗透高度降低50.72%。

关键词: 煤矸石, 喷射混凝土, 外加剂, 力学性能, 抗渗性

Abstract: Coal gangue shotcrete (CGS), as an eco-friendly construction material, is significantly influenced by the type and amount of admixtures used, among which accelerators and superplasticizers are widely applied due to their effective modification properties. This paper investigated the impact of varying dosages of accelerators and superplasticizers on the mechanical properties and impermeability of CGS through single-factor experiments to determine the optimal dosage. The findings were validated through rebound rate and large plate spraying tests. The results show that the inclusion of superplasticizer causes the compressive strength and splitting tensile strength of CGS to initially increase, then decrease, and rise again, achieving optimum properties at a 2.50% (mass fraction) dosage with no signs of permeability and good compactness. For accelerator content ranging from 0% to 3%, there is a slight increase in compressive and splitting tensile strength at 1 d age, which gradually decreases at 7 and 28 d. When the dosage increases from 3% to 12% (mass fraction), the strengths significantly decrease at all tested ages. Excessive accelerator (12%) notably exacerbates permeability. When the accelerator dosage is 3%, the top of CGS shows permeability. Rebound tests demonstrate that the synergistic effect of the accelerator and superplasticier enhances the flowability and bonding of CGS, reducing the rebound rate to 13.03%. The large plate spraying tests indicate that the optimized mix of CGS significantly enhances compressive strength and splitting tensile strength compared to ordinary CGS, with a 50.72% reduction in average penetration height.

Key words: coal gangue, shotcrete, admixture, mechanical property, impermeability

中图分类号:

TU528.53

查文华, 蔡雨凯, 许涛, 钱育冬. 外加剂掺量对煤矸石喷射混凝土力学性能和抗渗性的影响[J]. 硅酸盐通报, 2025, 44(5): 1676-1688.

ZHA Wenhua, CAI Yukai, XU Tao, QIAN Yudong. Influence of Admixture Dosage on Mechanical Properties and Impermeability of Coal Gangue Shotcrete[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(5): 1676-1688.

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