不同晶型碳酸钙对水泥浆体微观结构和性能演变的影响  

Influence of Different Calcium Carbonate Crystal on Microstructure and Performance Evolution of Cement Pastes

作　　者：杨慧慧[1,2,3] 张健 汪越[1,2,3] 毛宇光 胡翔 史才军 YANG Huihui;HANG Jian;WANG Yue;MAO Yuguang;Hu Xiang;SHI Caijun(Key Laboratory of Green&Advanced Civil Engineering Materials and Application Technology of Hunan Province,Hunan University,Changsha 410082,China;International Innovation and Cooperation Center for Green&Advanced Civil Engineering Materials of Hunan Province,Hunan University,Changsha 410082,China;Key Laboratory of Building Safety&Energy Conservation,Ministry of Education,Changsha 410082,China)

机构地区：[1]湖南大学绿色先进土木工程材料及应用技术湖南省重点实验室,长沙410082 [2]湖南大学,湖南省绿色与先进土木工程材料国际创新合作中心,长沙410082 [3]湖南大学,建筑安全与节能教育部重点实验室,长沙410082

出　　处：《硅酸盐学报》2025年第2期349-366,共18页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(52078204)。

摘　　要：研究了方解石和文石对水泥浆体微观结构和性能演变的作用机理。通过计算方解石和文石在水泥浆体中的填充效应、稀释效应、成核效应及化学效应,探究不同碳酸钙晶型对水泥浆体力学性能及微观结构演变的影响。结果表明:掺入适量的方解石或文石均可以促进水泥早期水化产物的生长和沉淀,水泥浆体早期抗压强度提高,此时碳酸钙的填充效应和成核效应发挥主要作用。水化7 d后,方解石或文石与铝相的反应程度提高,碳铝酸钙含量增多、水泥浆体孔隙率降低,化学效应的影响逐渐增加。文石相比于方解石,对于试件劈裂抗拉强度的提高主要与化学效应有关,反应产生的碳铝酸钙使文石与基体的粘结更加紧密。文石掺量20%~30%(质量分数),矿粉掺量5%~15%时,化学效应占比15%~21%,试件劈裂抗拉强度最多可提高39%。Introduction The use of calcium carbonate powder as a mineral admixture in cementitious materials can reduce CO_(2)emissions from clinker calcination and fossil fuel combustion,offering a low-carbon solution for sustainable cement production.Calcium carbonate can effectively fill the pores,refine the pore size,and promote the growth and precipitation of early hydration products of cement.On the other hand,calcium carbonate can react with the aluminum phase in cement to generate calcium carbon-aluminate,improving the mechanical properties of cementitious materials.There are two main crystal types of calcium carbonate in nature,calcite and aragonite.Due to the difference in density,stiffness and crystal structure of calcite and aragonite,calcite and aragonite-type calcium carbonate have different effects on the properties of cementitious materials.This paper elucidated the effects of different crystal types of calcium carbonate on the microstructure and mechanical properties of cement pastes and calculated the various effects of calcium carbonate in cement pastes,which would provide a solid and effective theoretical basis for the application of calcite and aragonite in engineering practice.Methods The raw materials used in this study include Portland cement(P·I 42.5),slag,calcite and aragonite.The calcite and aragonite were prepared by wet carbonation and analyzed for composition and purity by XRD and TG.Calcite and aragonite were separately added to the cement-slag composite system to prepare two groups of ternary systems with a water-cement ratio of 0.4.The simplex-centroid mixture design method was used to optimize the relative composition design of the raw materials in the cement pastes.According to the cement pastes composition design,20 mm×20 mm×20 mm specimens were moulded for testing compressive strength,?20 mm×40 mm specimens were moulded for testing splitting tensile strength,and?25 mm×25 mm specimens were moulded for pore structure analysis.The mechanical properties and pore structure of the specime

关 键 词：碳酸钙 方解石 文石 水泥浆体 力学性能 微观结构 

分 类 号：TU528[建筑科学—建筑技术科学]