摘要
通过在大体积混凝土浇块中埋设水工观测仪器的方法,对由双膨胀中热水泥和粉煤灰拌制的微膨胀混凝土(C15)进行了现场观测和分析.结果表明:该混凝土力学性能均能满足设计要求,其中28d的极限拉伸值为80μm/m,28d的抗裂能力为2.07MPa;该混凝土具有良好的微膨胀性能,其自生体积膨胀率在90d时约为30μm/m、在180d时为40～50μm/m;在大体积混凝土浇块内部,由温度作用产生的拉应力递增与由微膨胀作用产生的压应力递增基本同步发生,微膨胀作用能补偿自缩和部分冷缩,从而提高混凝土的抗裂能力.
Construction test of slight expansion(SE) concrete made from moderate heat Portland cement with double expansive sources(DE cement) and 20% fly ash was carried out and analysed with instruments buried in mass concrete in Lingjintan dam for measuring concrete deformation. The results indicate that mechanical properties of on-the-spot concrete satisfy the design needs. At the age of 28 d, the limit tensile strain and crack resistance of the concrete are 80 μm/m and 2.07 MPa respectively. The mass concrete has slight expansion. At the ages of 90 d and 180 d, the autogenous volume deformation reaches 30 μm/m and 40-50 μm/m respectively. It is concluded that in the interior of slight expansion concrete made from DE cement, autogenous volume slight expansion could compensate autogenous shrinkage and temperature shrinkage at the almost same time.
出处
《建筑材料学报》
EI
CAS
CSCD
2005年第3期279-283,共5页
Journal of Building Materials
基金
国家自然科学基金重大项目(59493604)
关键词
中热水泥
抗裂能力
微膨胀
施工试验
水工混凝土
moderate heat Portland cement
crack resistance
slight expansion
construction test
hydraulic concrete
