骨料中的黄铁矿反应及其对胶砂试件的破坏机理研究

Research on the reaction of pyrite in aggregates and its damage mechanism on mortar specimens

研究了不同条件下(干燥环境、自然环境、干湿循环、冻融循环),用含黄铁矿细骨料制备的胶砂试件中黄铁矿反应及其对试件的破坏机理。结果表明:干燥环境下,黄铁矿反应较弱,自然环境、干湿循环、冻融循环条件下,黄铁矿反应较强;自然环境下,黄铁矿氧化,造成延迟型钙矾石和铁锈膨胀型破坏;干湿循环条件下,黄铁矿反应形成的石膏溶出,无延迟钙矾石形成,破坏形式以铁锈膨胀破坏为主;冻融循环条件下,黄铁矿反应形成延迟型钙矾石,但氧化不充分,生成四氧化三铁。

The reaction of pyrite in rubber sand specimens prepared from pyrite containing fine aggregates under different conditions(dry environment,natural environment,dry-wet cycle,freeze-thaw cycle)and its damage mechanism on the specimens were studied.The results show that in dry environments,the reaction of pyrite is weak,while in natural environment,wet-dry cycles,and freeze-thaw cycles,the reaction of pyrite is strong.Under natural conditions,pyrite oxidizes,causing delayed ettringite and rust expansion damage.Under dry-wet cycle conditions,gypsum formed by pyrite reaction dissolves without delayed ettringite formation,and the main form of destruction is rust expansion and destruction.Under freeze-thaw cycle conditions,pyrite reacts to form delayed ettringite,but the oxidation is not sufficient,resulting in the formation of magnetite.