磷石膏用作连续施工抗裂缝剂的机理研究  

Mechanism Research on Application of Phosphogypsum as Anti-cracking Agent in Continuous Construction Method

作　　者：李佳[1] 资建民[1] 毛磊[2] 葛慧芝 

机构地区：[1]华中科技大学土木工程与力学学院,湖北武汉430074 [2]广东省长大公路工程有限公司第三分公司,广东广州511431 [3]河南省平顶山中亚路桥建设工程有限公司,河南平顶山467001

出　　处：《土木工程与管理学报》2015年第1期23-27,共5页Journal of Civil Engineering and Management

基　　金：广东省交通厅科技项目(2011-02-012);高等学校博士学科点专项研究基金(20100142120074)

摘　　要：利用磷石膏中可溶磷和氟对水泥的缓凝作用及Ca SO4·2H2O对水泥的缓凝膨胀作用,以原状磷石膏为主要膨胀和缓凝材料,柠檬酸为辅助调凝材料,开发出适用于半刚性基层沥青路面抗裂缝连续施工技术的基层抗裂缝剂,使水泥稳定材料初凝时间延长至8~10 h,并具有微膨胀性和致密性,减小水泥稳定碎石的空隙率,改善其温缩及干缩性能。以水泥凝结时间、胶砂强度、干缩性能为指标,通过室内试验确定出适合的抗裂缝剂掺量,分析了抗裂缝剂的缓凝及膨胀机理,并通过SEM微观电镜扫描,分析其微观抗裂机理。Phosphogypsum contains a small quantity of soluble phosphorus and fluorine and large amounts of dihydrate gypsum. Phosphorus and fluorine have significant effects on retarding the cement hydration process,while Ca SO4·2H2O can stimulate the generation of micro-expansile hydration products which can decrease the chemical shrinkage and dry shrinkage of cement. Based on the comprehensive effects of phosphogypsum on properties of cement,the phosphogypsum was used to develop the anti-cracking agent,with the citric acid as an auxiliary set retarder. This anti-cracking agent was added into the cement stabilized base materials to imply the Continuous Construction Method（ CCM）. On the one hand,anti-cracking agent prolongs the initial setting time of the base materials to 8 ~ 10 hours,on the other hand,micro-expansion materials generated from the reaction between cement-treated materials and anti-cracking agent contribute to reducing the porosity of cement-treated base and the contraction space for shrinkage. Strength,setting time and dry shrinkage were used as the evaluation indicators in laboratory tests to determine the suitable dosage of the addition agent. The anti-cracking mechanism was analyzed from the microscopic perspective by the scanning electronic microscope（ SEM）.

关 键 词：连续施工 抗裂缝剂 半刚性基层 缓凝剂 微膨胀 

分 类 号：U416.217[交通运输工程—道路与铁道工程] U414