低碱水泥对粉煤灰混凝土开裂敏感性影响研究

Study on the Influence of Low-alkaline Cement on Crack Susceptibility for the Concrete with Fly Ash

荆岳长江公路大桥地处洪涝灾害频发的长江中游地区,具有重要的交通枢纽作用。为保障混凝土的高性能、高耐久性,同时避免碱集料反应破坏、劣化混凝土结构,工程上部结构采用低碱水泥混凝土。本文在比较低碱水泥混凝土的力学、热学性能与普通混凝土规律一致的基础上,通过温度应力试验研究表明,粉煤灰对低碱水泥混凝土开裂敏感性影响与普通混凝土一致,且降低混凝土浇筑温度,更有利于降低低碱水泥混凝土应力积累速率,有利于控制混凝土早期开裂。

The location of Jing Yue Yangtze River bridge is in the middle of Yangtze River where the flood is frequent.This bridge is important for the road net of China.In order to ensure the durability and performance of concrete and to prevent the alkali-aggregate reaction from destroyed the elements,low alkaline cement is adopted to prepare concrete.This article compared the properties of mechanical and thermal for the concrete with low alkaline content cement to the normal concrete.The temperature-stress test indicated that the cracking sensitivity of fly ash for the concrete with low alkali content cement was the same with the normal concrete and the fly ash mixed can reduce the placement temperature,which was more advantageous to reduce stress accumulation rate and then to control early cracking effectively.