不同养护条件下掺合料对低温混凝土强度发展的影响

Study on compressive st rength of low temperature concrete with mineral admixture

针对低温条件下东北地区混凝土施工特点,采用恒低温一次冻结法和自然变低温多次冻结法,研究了在不掺防冻剂的情况下,不同养护条件下掺合料对低温混凝土强度的影响并测定混凝土在不同龄期的强度值。结果表明当复掺粉煤灰15%和硅灰5%时,混凝土的强度较之不掺加掺合料的混凝土增加28.8%,掺适量的掺合料的混凝土,恒低温养护条件下18h可达到抗冻临界强度6.9MPa,变低温条件下16h可达到抗冻临界强度6.7MPa。

It researched about the effects of mineral admixture on the compressive strength low-temperature concrete without antifreeze, with using once artificial freezing method and natural freezing method test the compressive strength of low-temperature concrete at different age.The result showed：with mixing fly ash（ 15% ） and silica fume （5%） can improve the strength of low-temperature concrete 28.8%. With fitting asmixture, the concrete reached resistant freezing critical strength of 6.9 MPa in 18h under -5 ℃ and 6,7 MPa in 16 h under 5--15℃.