外掺MgO混凝土技术在韩江高陂水利枢纽工程中的应用

Application of Concrete with MgO in Hanjiang Gaobei Water Control Project

针对韩江高陂水利枢纽工程采用外掺MgO筑坝技术,研究了外掺MgO水泥砂浆与一级配混凝土压蒸安定性、MgO常态混凝土自生体积变形和坝体混凝土中MgO均匀性、温度与应变。结果表明,在水泥砂浆与一级配混凝土体系中,外掺MgO的极限掺量分别为7.3%和11.5%,以水泥砂浆压蒸试件的MgO极限掺量作为混凝土配合比设计参考;MgO碾压混凝土的自生体积变形随养护温度提高而增大,养护温度相差10℃,外掺MgO常态混凝土自生体积变形增加或减少12.1×10^-6~31.1×10^-6;施工过程的碾压混凝土中MgO的均匀性好,外掺MgO坝体混凝土产生微膨胀补偿混凝土温度应力;控制变态混凝土与碾压混凝土的最高中心温度分别为41.6、33.1℃,应变值分别为60×10^-6、20×10^-6。研究结果可为外掺MgO碾压混凝土重力坝的温控抗裂措施提供借鉴。

Based on the damming technology of Hanjiang Gaobei Water Control Project with mixture MgO,the soundness of cement mortar and concrete with MgO,autogenous volume deformation of normal concrete uniformity of MgO,temperature and strain in dam concrete were studied.The results show that the limit dosage of MgO in cement mortar and concrete respectively are 7.3%and 11.5%.The dosage of MgO in cement mortar is used for mix proportion design as a reference.The autogenous volume deformation of MgO RCC increases with the increase of curing temperature.When the difference of curing temperature is 10℃,the autogenous volume deformation of normal concrete with MgO will increase or decrease by 12.1×10^-6-31.1×10^-6.The uniformity of MgO in RCC is good in the process of construction.The temperature stress of concrete is compensated by the expansion of dam concrete with MgO.The maximum central temperature in abnormal concrete and RCC are respectively 41.6℃and 33.1℃.The strain are respectively 60×10^-6 and 20×10^-6.The research results can provide reference basis for temperature control and anti-crack measures of RCC gravity dam with MgO.