摘要
喷射混凝土的凝结时间调节与早期强度发展和速凝剂的效能密不可分。本文通过甲酸、十八水硫酸铝、二乙醇胺、六水硝酸镁合成一种新型无碱液体速凝剂ALA,并对其促凝效能与作用机制进行研究。结果表明,ALA具有显著的促凝作用,随着ALA加量的增加,水泥砂浆的初终凝时间分别提前至4.6min和8.2min;ALA具有良好的温度适应性和外加剂相容性,与萘系/聚羧酸系减水剂协同作用时仍能发挥较好的促凝作用;ALA体系中引入的少量Mg^(2+),可与水泥水化产生的OH-结合并生成Mg(OH)_(2),这对固化水泥砂浆的体积收缩有一定的抑制作用;ALA中的Al^(3+)和SO_(4)^(2-)可在水化反应早期诱导大量钙矾石结晶沉积,以形成空间网络结构,促使水泥浆快速凝结。
The setting time adjustment and early strength development of shotcrete are closely related to the effectiveness of accelerator.This paper synthesizes a novel alkali free liquid coagulant ALA using formic acid,aluminum sulfate octadecahydrate,diethanolamine,and magnesium nitrate hexahydrate,and studies its coagulation efficiency and mechanism of action.The results show that ALA has a significant promoting effect on setting.With the increase of ALA dosage,the initial and final setting time of cement mortar can be advanced to 4.6 min and 8.2 min,respectively.ALA has good temperature adaptability and compatibility with additives,and can still exert a good promoting effect when synergistically used with naphthalene/polycarboxylate water reducers.The small amount of Mg^(2+)introduced into ALA system can combine with OH-generated by cement hydration to form Mg(OH)_(2),which has a certain inhibitory effect on the volume shrinkage of cured cement mortar.Al^(3+)and SO_(4)^(2-)in ALA can induce a large amount of ettringite crystal deposition in the early stage of hydration reaction,forming a spatial network structure and promoting rapid setting of cement mortar.
作者
张旭华
田明昆
张高寅
曾雪玲
辜涛
王世兰
曾辅俊
ZHANG Xuhua;TIAN Mingkun;ZHANG Gaoyin;ZENG Xueling;GU Tao;WANG Shilan;ZENG Fujun(China Railway Ninth Bureau Group Fifth Engineering Co.,Ltd.,Chengdu 611730;School of Materials and Chemistry,Southwest University of Science and Technology,Mianyang 621010;Jiahua Special Cement Co.,Ltd.,Leshan 614000)
出处
《中国建材科技》
CAS
2024年第4期21-24,共4页
China Building Materials Science & Technology
基金
中铁九局重大科研项目(2022-重大-14)
四川省自然科学基金项目(2024NSFSC0914)。
关键词
无碱液体速凝剂
硫酸铝
抑制收缩
促凝机制
alkali free liquid accelerator
aluminum sulfate
shrinkage inhibition
coagulation promoting mechanism
