硬石膏对蒸养混凝土力学性能及水化过程的影响  

Effect of Anhydrite on Mechanical Properties and Hydration Process of Steam-Cured Concrete

作　　者：王海亮 李祥飞 钱逸群 张毅 李永涛 WANG Hailiang;LI Xiangfei;QIAN Yiqun;ZHANG Yi;LI Yongtao(College of Materials Science and Engineering,Anhui University of Technology,Maanshan 243032,China;Anhui Hengtai New Material Co,Ltd,Maanshan 238171,China)

机构地区：[1]安徽工业大学材料科学与工程学院,马鞍山243032 [2]安徽省恒泰新材料有限公司,马鞍山238171

出　　处：《硅酸盐通报》2025年第3期892-904,共13页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51872137)。

摘　　要：硬石膏是提升蒸养混凝土力学性能的重要掺合料之一,本文通过力学性能、X射线衍射、热重分析、压汞测试、扫描电子显微镜、氯离子渗透及冻融循环试验研究了硬石膏掺量对蒸养混凝土抗压强度、水化产物、孔隙率、微观结构和耐久性的影响。结果表明,硬石膏提高了蒸养混凝土的线性膨胀率,当硬石膏掺量由0%(质量分数)提升至25%时,蒸养6 h后线性膨胀率由0.03%增大至0.25%。当硬石膏掺量为15%时,相较于空白试样,蒸养混凝土的3和28 d抗压强度分别提升14.4%和10.5%。硬石膏的掺入有助于提高钙矾石及水化硅酸钙(C-S-H)生成量,细化孔隙,降低有害孔数量,致密化蒸养混凝土内部结构,提高抗氯离子渗透能力。随着硬石膏掺量增加,体系中钙矾石生成量明显增加,后期开裂风险提高。当硬石膏掺量高于15%时,蒸养混凝土抗冻性能明显下降,硬石膏掺量应控制在5%~10%,此时蒸养混凝土具有较好的力学性能和耐久性。Anhydrite is one of the important admixtures to improve the mechanical properties of steam-cured concrete.In this paper,the effect of anhydrite content on the compressive strength,hydration products,porosity,microstructure and durability of steam-cured concrete was studied by mechanical properties,X-ray diffraction,thermogravimetric analysis,mercury intrusion test,scanning electron microscopy,chloride ion penetration and freeze-thaw cycles tests.The results show that anhydrite improves the linear expansion rate of steam-cured concrete.When the content of anhydrite increases from 0%(mass fraction)to 25%,the linear expansion rate increases from 0.03%to 0.25%after steam-curing for 6 h.When the anhydrite content is 15%,compared with the blank sample,the 3 and 28 d compressive strength of steam-cured concrete are increased by 14.4%and 10.5%,respectively.The incorporation of anhydrite helps to increase the amount of ettringite and hydrated calcium silicate(C-S-H),refine the pore,reduce the number of harmful pores,densify the internal structure of steam-cured concrete,and improve its chloride ion penetration resistance.With the increase of anhydrite content,the amount of ettringite in system increases significantly,and the risk of later cracking increases.When the content of anhydrite is higher than 15%,the frost resistance of steam-cured concrete decreases obviously.The content of anhydrite should be controlled at 5%~10%,at this time steam-cured concrete has better mechanical properties and durability.

关 键 词：硬石膏 蒸养混凝土 膨胀率 力学性能 微观结构 耐久性 

分 类 号：TU528[建筑科学—建筑技术科学]