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用两端带弯钩的钢纤维制作钢纤维增强混凝土梁形试件,研究了用硅灰代替不同量的普通硅酸盐水泥并通过掺加超塑化剂以降低混凝土的水灰比,发现当用硅灰代替10％水泥并同时使水灰比由0.5降至0.37,可使钢纤维增强混凝土小梁的抗弯极限强度与韧性分别提高了79％和63％,拔出试验结果表明,掺硅灰并同时掺塑化剂以降低水灰比有助于提高钢纤维与水泥砂浆的界面粘结强度。对钢与水泥基体界面区微观结构的研究结果表明,掺硅灰与降低水灰比可减少CH晶体在界面区的富集并消弱其取向性,增加C-S-H凝胶的含量并使界面区的孔结构得以明显改善,钢纤维增强混凝土的宏观力学性能与纤维——水泥基体的界面区微结构密切相关。
Steel fiber-reinforced concrete beam-shaped specimens were made from steel fibers with hooks at both ends. The use of silica fume instead of different amounts of ordinary portland cement was investigated to reduce the water-cement ratio of concrete by adding superplasticizers. When siliceous ash is used instead of 10% cement and the water-cement ratio is reduced from 0.5 to 0.37, the flexural ultimate strength and toughness of steel fiber-reinforced concrete girders are increased by 79% and 63%, respectively, and the pull-out test results show that The addition of silica fume and the simultaneous addition of a plasticizer to lower the water-cement ratio can help increase the interfacial bond strength between the steel fiber and the cement mortar. The results of the microstructure of the interface between steel and cement matrix show that the addition of silica fume and the reduction of water-cement ratio can reduce the enrichment of CH crystal in the interface area and weaken its orientation, increase the content of CSH gel and make the interface area The pore structure is significantly improved, and the macroscopic mechanical properties of steel fiber reinforced concrete are closely related to the microstructure of the interface area of the fiber-cement matrix.