不同胶凝材料的精细混凝土高温后力学性能

MECHANICAL PROPERTY OF FINE GRAINED CONCRETE WITH DIFFERENT CEMENTING MATERIAL AFTER EXPOSURE TO HIGH-TEMPERATURE

  • 摘要: 为了改善用于纤维编织网增强混凝土基体材料的精细混凝土的耐高温性能,该文进行了120个40mm× 40mm×160mm棱柱体的高温后抗折强度试验和240个40mm×40mm×40mm立方体的高温后抗压强度试验。考察了不同胶凝材料对精细混凝土试件高温后力学性能的影响,包括外掺纳米材料以及以高铝水泥作为主要胶凝材料的影响。结果表明:体积掺量为1.5%和3.0%纳米SiO2气凝胶粉末未能改善精细混凝土的耐高温性能,质量掺量为5.0%纳米陶瓷粉在目标温度TR=800℃时使基体混凝土的抗压和抗折强度分别提高84.2%和120.9%。当TR=800℃时,采用高铝水泥作为主要胶凝材料的试件力学性能均比普通精细混凝土试件大幅提高;各组掺入活性粉末的高铝水泥混凝土试件在TR= 800℃时,相对抗压和抗折强度均比未掺活性粉末时有所提高。

     

    Abstract: To improve the high temperature resistance of fine grained concrete for textile reinforced concrete matrices, 120 prism specimens (40mm×40mm×160mm) for flexural tests and 240 cube specimens (40mm×40mm×40mm) were prepared in this paper for compressive strength tests after exposure to high temperature. The effects of different cementing materials on mechanical properties of fine grained concrete were studied, including the effect of nanomaterial admixtures and the use of alumina cement as main cementing material. The results show that nanometer SiO2 aerogel powder cannot improve the high temperature resistance of fine grained concrete when volume fraction is 1.5% or 3.0%. Nanosized ceramic powder with quality content of 5.0% can improve the residual compressive and flexural strength of fine grained concrete by 84.2% and 120.9%, respectively, over that of concrete without nanosized ceramic powder at 800℃. When TR=800℃, mechanical properties of specimens with alumina cement as the main cementing material increase greatly compared with ordinary fine grained concrete specimens. Alumina cement concrete specimens with reactive powder mixed have higher relative residual compressive and flexural strength than those without reactive powder at 800℃.

     

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