纤维掺量对混凝土力学性能和热工性能的影响

Influence of fiber content on mechanical properties and thermal performance of concrete

在常温下,使用搅拌机将水泥、纤维、粉煤灰、骨料和水等进行混合搅拌,随后放入振动台上进行振动,养护28d,制备纤维混凝土,其中掺入的粉煤灰质量分数为0~20%、纤维质量分数为0~10%;研究了粉煤灰、碳纤维、棉纤维和聚丙烯纤维的掺量对混凝土的力学性能和热工性能的影响。结果表明:随着粉煤灰掺量的增加,混凝土的抗压强度和抗拉强度均先升高后下降;随着纤维掺量的增加,混凝土的抗压强度和抗拉强度呈现先增大而后下降的趋势;在掺入粉煤灰质量分数10%、纤维质量分数5%时,3种纤维混凝土的强度均达到最高,其中碳纤维混凝土的抗压强度为52.8MPa、抗拉强度为4.24MPa,棉纤维混凝土的抗压强度为51.7MPa、抗拉强度为4.07MPa,聚丙烯纤维混凝土的抗压强度为50.2MPa、抗拉强度为3.81MPa;在不掺入粉煤灰的条件下,随着纤维掺量的增加,3种纤维混凝土的导热系数均逐渐下降,热工性能提高,掺入质量分数5%的纤维,在满足混凝土强度的同时可达到建筑节能的目的。

Three kinds of fiber reinforced concrete were prepared by mixing cement,fiber,fly ash,aggregate and water in a mixer and then vibrating the mixture on a vibration platform prior to curing for 28 d at room temperature.The mass fraction of fly ash and fiber was 0-20% and 0-10%,respectively.The influence of fly ash,carbon fiber,cotton fiber and polypropylene fiber on the mechanical and thermal performance of the concrete was studied.The results showed that the compressive strength and tensile strength of the concrete first increased and then decreased with the increase of fly ash content and fiber content as well;the compressive strength and tensile strength of the three kinds of fiber reinforced concrete were maximized as 52.8 MPa and 4.24 MPa for carbon fiber reinforced concrete,51.7 MPa and 4.07 MPa for cotton fiber reinforced concrete and 50.2 MPa and 3.81 MPa for polypropylene fiber reinforced concrete when the mass fraction of fly ash and fiber was 10%and 5%,respectively;the thermal conductivity of the three kinds of fiber reinforced concrete gradually decreased and the thermal performance increased with the increase of fiber content without adding fly ash;and the fiber reinforced concrete containing 5%fiber by mass fraction simultaneously satisfied the requirement of concrete strength and building energy saving.