钢纤维对喷射混凝土方板早龄期弯曲性能的影响

摘要

In order to study the mechanical properties of steel fiber reinforced shotcrete at early age,plates with different fiber use levels were tested in accordance with European specification for sprayed concrete (EFNARC),and the steel mesh reinforced concrete plates were also tested as comparison.The specimens were tested at the age of 10,30,48 h,respectively.The load-deflection curves and the energy absorption ability were compared,the bending behaviors of the steel fiber reinforced plates with different fiber use levels and the steel mesh reinforced plates were analyzed.The results show that steel fiber can enhance the punching shear capacity greatly at early age,the failure pattern of the steel fiber reinforced plate is changed from punching shear to flexural failure when the fiber use level is larger than 20 kg/m3.%为了研究隧道支护层钢纤维喷射混凝土在早龄期的力学性能,参照欧洲喷射混凝土标准(EFNARC),对不同掺量的钢纤维喷射混凝土方板进行试验研究,并与传统钢筋挂网喷射混凝土方板进行了对比.通过对10,30,48 h龄期钢纤维喷射混凝土方板的荷载-位移曲线及能量吸收能力的比较,分析了不同钢纤维掺量喷射混凝土方板与钢筋挂网喷射混凝土方板的弯曲性能.结果表明:钢纤维可以显著提高早龄期混凝土的抗冲切能力;当钢纤维掺量超过20 kg/m3时,钢纤维喷射混凝土方板由脆性冲切破坏变为弯曲破坏.