摘要
工程调查显示,部分大体积混凝土桥墩发生开裂的特点是,裂纹在浇筑后7 d拆模时即出现在承台以上实心结构的中间位置,呈上下走向,并且在桥墩两面对称出现,判断裂纹主要是由于施工中内降温和外保温措施不充分造成的;试验研究显示,掺合料替代水泥的比例越高,降低水化热的作用越显著,粉煤灰降低水化热的作用略高于矿渣粉,将粉煤灰与矿渣粉复合后替代40%的水泥,即能够保证工程的混凝土强度设计要求,又能够显著降低水化热;同时,建议施工时在钢模板内衬织物来提高外保温效果。
The characteristic of cracking of bulk mass concrete pier,on the base of researching on engineering,is that the crack appears on middle of construction when form removal at 7 days age.Normally,the crack exhibits up and down trend,and it is found symmetrically on both side of pier.It is indicated that both inner cooling and outer keeping warm steps are so inadequate during the process of building that the temperature difference between inner and outer of construction raises significantly.Experimentation research shows that the more replacement of admixtures to cement,the lower the hydration heat.Fly ash can decrease the hydration heat more than granulated blast furnace slag.If blend admixture of fly ash and granulated blast furnace slag replace 40% volume of cement,compression strength of concrete can meet the requirement of engineering design,and can reduce the hydration heat a lot.This paper suggests lining fabric on steel formwork to advance keeping warm efficiency.
出处
《混凝土》
CAS
CSCD
北大核心
2010年第10期133-135,共3页
Concrete
基金
河海大学海岸灾害及防护教育部重点实验室开放基金
关键词
大体积
混凝土
抗开裂性
bulk mass
concrete
crack resistance performance
