凝灰岩石粉在复合胶凝材料中的火山灰活性及水化性能评估  

Pozzolanic Reactivity and Hydration Properties Assessment of Tuff Powder in Composite Cementitious Materials

作　　者：王旭昊 侯鑫 甘珑 汪愿 边庆华 张久鹏[1] WANG Xuhao;HOU Xin;GAN Long;WANG Yuan;BIAN Qinghua;ZHANG Jiupeng(School of Highway,Chang’an University,Xi’an 710064,China;PowderChina Chengdu Engineering Corporation Limited,Chengdu 610072,China;Gansu Road and Bridge Third Highway Engineering Corporation Limited,Lanzhou 730050,China)

机构地区：[1]长安大学公路学院,西安710064 [2]中国电建集团成都勘测设计研究院有限公司,成都610072 [3]甘肃路桥第三公路工程有限责任公司,兰州730050

出　　处：《材料导报》2022年第16期143-150,共8页Materials Reports

基　　金：国家重点研发计划项目(2021YFB2601000);国家自然科学基金(52178185);中国博士后科学基金(2021MD703885)。

摘　　要：为响应国家“碳达峰、碳中和”战略,实现水泥行业绿色可持续发展,拟探究凝灰岩石粉作为辅助胶凝材料替代部分水泥后对水泥基材料的水化影响机理,以推动凝灰岩石粉在实际工程中的应用。本工作对花岗岩石粉、粉煤灰与凝灰岩石粉展开对比研究,首先基于火山灰活性指数法评价三者的火山灰活性大小,而后利用抗压强度测试以及X射线衍射(XRD)、热重-差热分析(TG-DTA)、扫描电镜(SEM)等微观手段研究了水泥-石粉及水泥-粉煤灰复合浆体的强度和水化发展规律,最后还对温室气体排放进行了评估。结果表明:凝灰岩石粉具有较弱的火山灰活性,其火山灰活性指数为52.5%,小于65%,一般情况下,不可直接作为水泥砂浆和混凝土的天然火山灰质材料;凝灰岩石粉在水泥基材料中存在晶核作用,可以促进水泥的早期水化,晶核作用的大小和粉体细度相关,细度较小的凝灰岩石粉对水化的促进作用强于细度偏大的花岗岩石粉;从化学结合水分析得出,受凝灰岩石粉晶核效应以及火山灰反应的影响,20%(质量分数,文中未特殊说明皆为质量分数)凝灰岩石粉复合体系与20%粉煤灰复合体系的水化程度基本一致。To respond to the “carbon peak, carbon neutral” strategy and realize the green and sustainable development of the cement industry, it is proposed to study the mechanism of the hydration effect on cement-based materials when tuff powder is used as supplementary cementitious material to replace part of cement. Through the research, we hope to promote the application of tuff powder in a practical project. In this work, a comparative study was carried out using granite powder, fly ash and tuff powder. The pozzolanic reactivity was evaluated by the pozzolanic reactivity index method, and then the strength and hydration development of cement-powder and cement-fly ash composite system were studied by compressive strength test and microscopic analysis means such as X-ray diffraction(XRD), thermogravimetry-differential thermal analysis(TG-DTA) and scanning electron microscope(SEM). Finally, greenhouse gas emissions were assessed. The results showed that tuff powder had a weak pozzolanic reactivity. Specifically, its pozzolanic reactivity index was 52.5%, which was less than 65%. In general, it cannot be directly used as natural volcanic ash material for cement mortar and concrete. Tuff powder in cementitious materials will play the role of crystal nucleation, which can promote the early hydration of cement. The strength of nucleation effect was related to the fineness of the powder, and the smaller tuff powder had a stronger role in promoting hydration than the granite powder with a larger fineness. From the results of chemically bound water analysis, it was concluded that the hydration degree of tuff powder-cement composite system and fly ash-cement composite system was the same when the addition amount of mineral admixture was 20%, influenced by the nucleation effect and pozzolanic reactivity of tuff powder.

关 键 词：凝灰岩石粉 粉煤灰 花岗岩石粉 绿色可持续发展 水泥基材料 

分 类 号：TU528[建筑科学—建筑技术科学]