海水干湿循环作用下地聚物基珊瑚骨料混凝土力学性能的研究  

Mechanical Properties of Geopolymer-based Coral Aggregate Concrete Under Dry-wet Cycles of Seawater

作　　者：张白 彭晖 杨致远 ZHANG Bai;PENG Hui;YANG Zhiyuan(School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,China;School of Civil Engineering,Southeast University,Nanjing 210096,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114 [2]东南大学土木工程学院,江苏南京210096

出　　处：《材料导报》2024年第23期76-84,共9页Materials Reports

基　　金：湖南省自然科学基金(2024JJ6054);长沙市自然科学基金(kq2402026)。

摘　　要：利用远海岛礁地区可获得的海洋资源(如海水、海砂和废弃的珊瑚礁)制备海水珊瑚骨料混凝土(CAC),有助于缩短海洋工程项目的建造工期并降低建设成本。然而,珊瑚骨料的多孔和脆性特征影响着CAC及其结构的力学和耐久性能。本研究考虑使用低碳且耐腐蚀的矿渣-粉煤灰基地质聚合物替代普通硅酸盐水泥制备地聚物基海水珊瑚骨料混凝土(GPCAC),并开展了海水干湿循环作用下GPCAC力学及耐久性的研究,同时采用SEM、XRD等技术手段剖析海水环境作用后混凝土力学性能的损伤机理。研究表明:GPCAC在遭受腐蚀环境作用后表现出比CAC更为优异的抗海水侵蚀性。当试件处于45℃海水干湿循环环境作用12个月后,CAC立方体的抗压强度和弹性模量分别削减了9.7%和8.6%,而GPCAC弹性模量仅降低了6.2%,甚至其立方体抗压强度增长了5.9%。地聚物密实的微观结构、优良的孔结构以及稳定的水化产物是其抗海水侵蚀性能优于水泥基胶凝材料的原因。Seawater coral aggregate concrete(CAC),prepared with locally available marine resources(e.g.seawater,sea-sand,and wasted coral aggregates)on reef or island areas,is helpful to shorten construction period and reduce construction costs of offshore projects.However,the porosity and brittleness of coral aggregates will affect the mechanical properties and durability of CAC and CAC structures.In this work,low-carbon and well-durable geopolymers were used instead of ordinary Portland cement to prepare geopolymer-based seawater coral aggregate concrete(GPCAC),and it’s mechanical properties and durability under seawater wet-dry cycles were explored,meanwhile the deterioration mechanism of the mechanical properties of the concrete was evaluated by scanning electron microscopy(SEM)and X-ray diffraction(XRD)techniques.The results indicated that GPCAC exhibited better seawater erosion resistance than CAC after exposure to seawater dry-wet cycle environments.When subjected to 45℃seawater conditions in wet-dry cycles for 12 months,the cubic compressive strength and elastic modulus of CAC were reduced by 9.7%and 8.6%,respectively,while the elastic modulus of GPCAC was only reduced by 6.2%,and even the cubic compressive strength of GPCAC increased by 5.9%.It was concluded that the dense microstructure,excellent pore structure,and stable hydration products of geopolymers are the reasons for their superior performance against seawater corrosion to cement-based materials.

关 键 词：地质聚合物 珊瑚骨料混凝土 力学性能 海水干湿循环 劣化机理 

分 类 号：TU377[建筑科学—结构工程]