【摘要】 碾压混凝土(RCC)层面结合优劣将直接影响碾压混凝土坝体的强度、抗渗和安全运行 ,而层面成型的间隔时间则是控制层面结合的关键所在。传统上一直以宏观的初凝时间为判断碾压混凝土是否失去触变复原特性的依据 ,作者利用高倍连续变焦显微系统追踪观察水泥砂浆的细观晶体构架形成过程 ,并与宏观测定的初凝时间对比。观察结果表明 ,早在初凝之前 ,砂浆的细观晶体构架已经基本形成 ,此后若加以扰动会破坏已经形成的构架。层面成型的间隔时间应控制在从浇注到初凝时间的三分之一到二分之一。更多还原

【Abstract】 There is important effect on strength, inpermeability and safety of concrete dam to the connection of two layers in RCC (roller compacted concrete), and the interval time between two RCC Layers is the key of the connection. Traditionally, initial setting time is taken as the criterion for evaluating if the RCC has losed the ability of thixotropic restoration. The process of microstructural formation in mortar is observed with the continuous zoom microscope system, and the result is compared with the initial setting time. The Experimental results showed that the time when microstructure forms is much earlier than initial setting time. Therefore any disturbance after the time will destroy the microstructure. The authors suggest that one third to one half of the initial setting time should be taken as the imterval time.更多还原