粉煤灰、炉渣对混凝土抗压强度和吸水率的影响

Influence of fly ash and slag on compressive strength and water absorption of concrete

为了缓解建材压力,提高工业废料的资源化利用率。研究粉煤灰替代水泥、炉渣替代粗骨料及骨料粒径对不同龄期(3d、7 d、28 d)混凝土抗压强度和吸水率的影响(粉煤灰质量替代率分别为0%、5%、10%、15%、20%,炉渣质量替代率分别为0%、3%、5%、8%、10%,骨料粒径分别为5~20 mm,5~25 mm,5~31 mm,5~40 mm)。结果表明:随着炉渣替代率的增大,混凝土28 d抗压强度呈现先增大后减小的趋势;随粉煤灰替代率的增大,混凝土28 d抗压强度呈“M”型发展趋势。在炉渣、粉煤灰替代率对混凝土影响中,粉煤灰替代率15%、炉渣替代率5%时,28 d抗压强度为31.01 MPa,满足强度要求且能提高工业废渣利用率。混凝土的抗压强度随着粗骨料粒径的增大而减小,骨料粒径不超过20 mm时,28 d抗压强度达到33.62 MPa。在粉煤灰替代率为15%、炉渣替代率为5%,且骨料粒径不超过20 mm时,能满足C30混凝土的强度要求。

In order to alleviate the pressure of building materials and improve the resource utilization rate of industrial waste. The effects of fly ash replacing cement, slag replacing coarse aggregate and aggregate particle size on the compressive strength and water absorption of concrete at different ages(3 d, 7 d, 28 d) were studied(the quality substitution rate of fly ash were 0%, 5%, 10%, 15%,20%, the slag quality substitution rate were 0%, 3%, 5%, 8%, 10%, and the aggregate particle size were 5-20 mm, 5-25 mm, 5-31mm, 5-40 mm, respectively). The results showed that with the increased of slag substitution rate, the 28 d compressive strength of concrete increased first and then decreased;with the increased of fly ash replacement rate, the 28 d compressive strength of concrete showed a“M”type development trend. In the influence of slag and fly ash replacement rate on concrete, when the fly ash replacement rate was 15 % and the slag replacement rate was 5 %, the 28 d compressive strength was 31.01 MPa, which met the strength requirements and can improved the utilization rate of industrial waste slag. The compressive strength of concrete decreased with the increased of coarse aggregate size. When the aggregate size was less than 20 mm, the 28 d compressive strength reached 33.62 MPa.When the substitution rate of fly ash was 15 %, the substitution rate of slag was 5 %, and the aggregate particle size was not more than 20 mm, the concrete strength requirements of C30 can be met.