This work presents results of the first study of the variation by exposure to high temperatures from two stay-in-place polyvinyl chloride (SIP-PVC) formwork concrete exposed to the ISO 834 fire curve. A systematic sampling based on the proximity of the fire and the spalling of the concrete was carried out and microstructural, thermal, crystallographic and spectroscopic changes were studied according to the degree of affectation by fire using SEM, TGA-DTA, XRD and FTIR. The response to high temperature exposure of the microstructure of SIP-PVC formwork concrete after fire was established using the experimental results. Results show a relationship between the microstructure of concrete paste and exposure temperature, as well as, the relationship between exposure temperature and dehydration of calcium hydrates, CSH gel and Portlandite and decarbonation of Calcite. These reactions can be considered as tracers of the degree of exposure to high temperatures from stay-in-place PVC formwork concrete.

这项工作介绍了两种暴露于ISO 834防火曲线的现浇聚氯乙烯（SIP-PVC）模板混凝土因高温暴露而引起的变化的首次研究结果。根据火的临近程度和混凝土剥落情况进行了系统取样，并根据火的影响程度，使用SEM，TGA-DTA，XRD和FTIR研究了火的微结构，热学，晶体学和光谱变化。利用实验结果确定了SIP-PVC模板混凝土在火灾后对高温暴露的响应。结果表明，混凝土浆的微观结构与暴露温度之间的关系，以及暴露温度与水合钙的脱水之间的关系，CSH凝胶和硅酸盐和方解石脱碳。这些反应可视为PVC模板混凝土在高温下暴露程度的示踪剂。