首页> 外文期刊>Fire and materials >Thermal and mechanical properties of light-weight concrete exposed to high temperature
【24h】

Thermal and mechanical properties of light-weight concrete exposed to high temperature

机译:轻型高温混凝土的热力学性能

获取原文
获取原文并翻译 | 示例
       

摘要

The extensive studies devoted so far to normal-strength light-weight aggregate concrete (LWAC or LWC) have exhaustively clarified its behaviour in ordinary conditions. However, the introduction of high-performance light-weight aggregate concrete (HPLWAC or HPLWC), containing such pozzolanic components as microsi-lica and fly ash, raises some concerns, for instance about the behaviour at high temperature and after cooling. To investigate the temperature-induced mechanical damage, both in compression and tension, of silica-fume HPLWCs, a systematic research program was carried out at the Politecnico di Milano on materials residual behaviour (testing after cooling down to room temperature). Three concrete mixes (Normal-Strength Concrete = NSC, f_c~(20) = 30 MPa; Light-Weight Concrete = LWC, f_c~(20)≈40 MPa; and High-Performance Light-Weight Concrete=HPLWC, f_c~(20)≈60 MPa), five temperature levels (20,105,250,500 and 750 ℃, no loads applied during heating), one thermal state (after cooling), three nominally-equal tests for each case (for repeatability) were planned, bringing the total number of specimens to 120 (45 tested in compression, 45 in direct tension and 30 in indirect tension by splitting). At the same time, the thermal diffusivity of the materials was evaluated up to 750 ℃ (4 specimens). The results show that HPLWC is somewhat more temperature-sensitive than both NSC and LWC, but this extra sensitivity is counterbalanced by HPLWC s lower diffusivity. Its better insulation properties are advantageous for the concrete in axially-loaded members and for the tension bars in the beams, as demonstrated by the thermo-mechanical analyses of three typical R/C sections (rectangular, T and slab sections) carried out in the second part of the paper.
机译:迄今为止,针对普通强度轻骨料混凝土(LWAC或LWC)的广泛研究已经详尽阐明了其在正常条件下的性能。但是,引入高性能的轻质骨料混凝土(HPLWAC或HPLWC),其中包含火山灰成分(如硅微粉和粉煤灰),引起了一些担忧,例如高温和冷却后的性能。为了研究温度对二氧化硅烟气中的HPLWC的压缩和拉伸机械损伤,在Politecnico di Milano进行了一项系统的研究程序,研究材料的残留行为(冷却至室温后进行测试)。三种混凝土混合物(普通强度混凝土= NSC,f_c〜(20)= 30 MPa;轻质混凝土= LWC,f_c〜(20)≈40MPa;高性能轻质混凝土= HPLWC,f_c〜( 20)≈60MPa),五个温度水平(20,105,250,500和750℃,加热期间不施加负载),一种热状态(冷却后),每种情况下计划进行三项名义上相等的测试(以确保可重复性),从而得出总数样品至120个(压缩测试45个,直接拉伸测试45个,通过分裂测试间接拉伸30个)。同时,评估了材料在高达750℃的热扩散率(4个样品)。结果表明,HPLWC的温度敏感性比NSC和LWC都高,但是这种额外的敏感性被HPLWC较低的扩散性所抵消。它的更好的隔热性能对于轴向受力构件中的混凝土和梁中的拉力杆都是有利的,正如在施工过程中对三个典型的R / C截面(矩形,T形和平板截面)进行的热机械分析所证明的那样。本文的第二部分。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号