矿渣聚丙烯纤维水工混凝土抗弯性能研究

Flexural performance of polypropylene fiber reinforced hydraulic concrete containing slag

为研究聚丙烯纤维和磨细粒化高炉矿渣对水工混凝土抗弯性能的影响,以普通混凝土试样为对照,对聚丙烯纤维混凝土、矿渣混凝土、矿渣聚丙烯纤维混凝土试样进行了简支梁法弯折性能试验,并通过扫描电镜对试样的微观结构进行观测和分析。结果表明,掺入适量聚丙烯纤维,可抑制微裂缝的产生和扩散,延缓和抑制宏观裂缝的出现和发展,提高混凝土抗弯强度,同时还能提高持荷变形能力和混凝土吸收能量的能力以及混凝土的韧性。适量矿渣及其水化物的掺入,增加了基体微观结构的密实性,可提高混凝土抗弯强度。化学和物理分析认为,掺入0.1%-0.6%聚丙烯纤维和低于55%含量的矿渣,复合效应显著。

A series of third-point bending tests for beams were carried out to investigate the effect of high replacement of slag and polypropylene fiber on flexural properties of hydraulic concrete.Four types of concrete beams had been tested,which were plain concrete beams as control specimens,polypropylene fiber reinforced concrete beams,slag concrete beams and polypropylene fiber together with slag reinforced concrete beams.We used SEM to conduct observation and analysis to the micro-structure of specimens.The experimental results show that,moderate mixing amount of polypropylene fibers are able to control the propagation of micro fracture and the development of macro fracture in concrete,and to improve flexural performance of concrete.Fiber is seen to enhance the pre-peak as well as post-peak region of the load-deflection curve,causing an increase in energy absorbing capability.Slag particles can also benefit the density of concrete microstructure,thus improve flexural strength.The positive synergies of polypropylene fiber and slag are significantly both on physical and chemical aspects at the range from 0.1% to 0.6% volume fiber content with the range from 0 to 55% slag content.