摘要
针对超高索塔锚固区的特点,按照抗裂最优,又能高空泵送的原则,制备了钢纤维混凝土,并对其构件的抗裂性能进行了研究.优选出的钢纤维混凝土1h内泵送性能良好,可以实现一次泵送到306m的目标.经过计算,纤维体积率为0.8%的钢纤维混凝土能使混凝土结构裂缝的最大宽度降低32%.通过对索塔锚固区的足尺模型试验研究得出:该钢纤维混凝土不仅能够显著提高索塔锚固区混凝土结构的抗裂度和极限载荷,而且能使混凝土结构正常使用极限状态下的载荷增大了将近40%.试验结果也表明其能显著抑制塑性收缩,并且能使干燥收缩值降低50%,同时又具有较高的抗拉强度和钢筋握裹力.
The mix ratio of steel fiber reinforced concrete （SFRC） is optimized by the principles that workability meets the pumping demand and the anti-cracking performance is optimal. The effect of SFRC on the anti-crack performance of reinforced concrete （RC） member is analyzed. It is found that the admixture has good preservation of moisture and adhesion and the fibers distribute homogeneously in one hour out of machine. According to the pumping results, the SFRC can be pumped vertically up to 306 m. Based on the standard computation formula of cracks, the maximum crack width of RC member with 0. 8% steel fiber （by volume） is about 32% lower than that of RC member. A experimental research on the full-scale model tests for the steel and concrete composite anchorage zone on the pylon shows that the SFRC not only remarkably increases the crack resistance and the ultimate load, but also makes an enlargement of nearly 40% on the load under normal service conditions, it is also indicated that plastic shrinkage cracking of SFRC in which volume fraction of steel fibers is 0. 8 % can be restrained obviously and the unrestrained drying shrinkage can be diminished by about 50% at early age. The results confirm that the SFRC can lessen the shrinkage crack of concrete, enhance markedly the bond stress of steel-rebar and the direct tensile strength.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2007年第1期123-127,共5页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金重点资助项目(59938170)
江苏省重大工程资助项目(STDQ-04HT20SY-010)
