超高性能混凝土低温性能的试验研究

Research on Low Temperature Resistance Ultra-High Performance Concrete

文中研究早龄期低温环境对UHPC力学性能的影响规律,以及硝酸钙、硫氰酸钠、三乙醇胺、快凝快硬水泥、促强减缩剂对UHPC工作性能和低温环境下强度的影响。结果表明,温度大于0时,环境温度对UHPC强度影响较小;在低于-5℃条件下,温度对UHPC强度影响较大。三乙醇胺复合早强剂有助于UHPC强度发展,掺加2.5%的三乙醇胺,对混凝土工作性能影响小,-5℃转标养时,28 d抗压强度为126.7 MPa,抗折强度为14.1 MPa,抗拉强度为7.5 MPa。快凝快硬水泥、促强减缩剂有助于UHPC低温环境下早期强度发展,但对混凝土工作性能影响较大。

The effect of low temperature in early age on the development of mechanical properties of UHPC was studied.The effects of calcium nitrate,sodium thiocyanate,triethanolamine,fast-setting and quick-hardening cement and strength promoter on the workability and strength of UHPC under low temperature environment were studied.The results show that the temperature environment has little effect on the development of UHPC intensity above 0.Under the condition of less than-5℃,the temperature environment has a great influence on the development of UHPC intensity.Triethanolamine composite early strength agent is conducive to the development of low-temperature UHPC strength,mixed with 2.5%triethanolamine,has little effect on concrete workability,-5℃transfer standard maintenance for 28 d compressive strength of 126.7 MPa,flexural strength of 14.1 MPa,tensile strength of 7.5 MPa.Fast-setting and fast-hardening cement and strength reducer are helpful for the early strength development of UHPC at low temperature,but have a great impact on the workability of concrete.