防核辐射混凝土高温稳定性能试验研究

Experimental research on the high temperature stability of radiation shielding concrete

利用综合热分析仪、热膨胀仪、X射线衍射仪及扫描电镜,通过测试防核辐射混凝土中水泥石的热分解过程、高温矿物组成变化、热膨胀性能、高温后抗压强度变化,砂浆的热膨胀性能和混凝土高温后微观形貌变化及抗压强度变化,研究了防核辐射混凝土的高温热稳定性能。结果表明,经700℃高温后,水泥石中C-S-H凝胶网状结构出现破碎,数量减少,其主要矿物组分为CaO、Ca(OH)2、C3S和β-C2S,集料与水泥石界面结构松散,并出现裂纹;40～600℃过程中,水泥石和砂浆呈先膨胀后收缩的变化趋势,且水泥石的热膨胀系数远大于砂浆。

The high temperature stability of radiation shielding concrete is studied according to testing the thermal decompositioncement process,the change of mineral composition,thermal expansion and compressive strength of paste,the thermal expansion of mortar and the change of mi-cro-morphology and compressive strength of radiation shielding concrete after high temperature by comprehensive thermal analyzer,thermal expan-sion instrument,XRD and SEM.The results indicate that the reticular formation of C-S-H is broken and the quantity decreased,the major mineral composition of paste is CaO、Ca（OH） 2 、C 3 S and β-C 2 S,the interface between aggregate and paste of concrete become loosely-structured and crack ing,andduring40~600℃,thepasteandmortarfirstlyexpand,andthenshrink,andtheshrinkagerateofpasteismuchgreaterthanthatofmortar.