Damaging Formula of the Frost Resistant Concrete with Poor Quality of Coarse Limestone Aggregate

In this paper, concrete with limestone coarse aggregate was studied due to frost action in saline and nonsaline environments. The main focus is to explain the damaging formula of concrete with poor quality of limestone aggregate in frost actions. All investigated concretes fulfill the recommendations of the European standard EN 206, Concrete--Specification, Performance, Production and Conformity limiting values for composition and properties of concrete （maximum W/C （water/cement） ratio, minimal class of compressive strength, minimal mass of cement and minimal percentage of entrained air）. The damaging formula of the frost resistant concrete is studied through scaling test of concrete during freeze/thaw process, frost resistant test of coarse limestone aggregate and chemical analysis of limestone. Experiments results showed that there is a correlation between CaO/MgO ratio and Al2O3 of limestone and frost resistance of concrete, using chemical composition for determining potential ACR （alkali-carbonate reactivity） will indicate higher risk of damaging effect of concrete.

确定混凝土粗骨料配合比方法的探讨

本文按照富勒级配理论进行粗骨料搭配组合,可以获得最大的堆积密度和最小孔隙率。以富勒级配颗粒组成为标准,用骨料的筛析结果,可以计算出向富勒级配靠近的搭配比例。要实现骨料最佳的搭配组合,各骨料自身合理的颗粒分布是关键;用三级复配的方式可明显改善混合骨料的堆积状态;应依据富勒级配要求制定骨料级配标准,对供应商提出要求。