超高性能混凝土抗高温爆裂性能试验研究

Explosive Spalling Resistance of Ultrahigh Performance Concrete

摘要:

测定了含粗骨料超高性能混凝土与活性粉末混凝土的不同含湿量（质量分数，下同）试件在从常温加热至800℃过程中的抗高温爆裂性能.结果表明：含粗骨料超高性能混凝土的抗高温爆裂性能优于活性粉末混凝土.粗骨料的存在不仅降低了超高性能混凝土的内部应力，而且增大了钢纤维在砂浆基体中的分布密度，因此起到减轻混凝土爆裂的作用.试验中大量粗骨料从砂浆基体中剥离，这证实蒸汽压力是导致超高性能混凝土发生高温爆裂的重要因素.2种超高性能混凝土的0%含湿量试件均未发生爆裂，而含湿量在25%及以上的试件均发生了爆裂，且含湿量越大，试件爆裂越严重.可以用爆裂发生的温度范围和爆裂声响次数来判断超高性能混凝土高温爆裂的严重程度.

Abstract:

Ultrahigh performance concrete with coarse aggregate(UHPC(CA)) and reactive powder concrete(RPC) were exposed to high temperature to investigate their explosive spalling resistance experimentally. The results indicate that UHPC(CA) exhibits better explosive spalling resistance than RPC. Coarse aggregates can decrease the intemal stress and increase the distribution density of steel fiber in mortar, thus provide a beneficial effect on alleviating the explosive spalling of UHPC(CA). The fact that lots of coarse aggregates spalled off the mortar matrix proved that the vapor pressure played a crucial role in inducing the explosive spalling of concrete. For both UHPC(CA) and RPC, the specimens with 0% moisture content suffered no explosive spalling and the specimens with moisture content not less than 25% encountered explosive spalling. Furthermore, the higher the moisture content, the more severe the explosive spalling of concrete specimens. The temperature range and the number of loud voices occurred during explosive spalling can be used to evaluate the severity of explosive spalling.