外掺钢纤维混凝土早期力学性能的试验研究

为研究外掺钢纤维对混凝土早期力学性能的影响,以不同钢纤维掺量和时间龄期为变化参数,设计了168个外掺钢纤维混凝土棱柱体试块进行早龄期轴心抗压强度及弹性模量试验.试验观察了试件的破坏过程及形态,获取了不同时间龄期外掺钢纤维混凝土的强度及弹性模量等关键特征参数,揭示了不同外掺钢纤维掺量对混凝土早龄期强度及弹性模量的影响规律,并推导出不同时间龄期外掺钢纤维混凝土强度和弹性模量的计算式,研究结果表明:外掺钢纤维对混凝土早期弹性模量的有所提高,对混凝土早期轴心抗压强度的提高不显著.当外掺钢纤维≥40 kg/m3时,可有效提高3、28 d龄期混凝土的弹性模量,因此,建议外掺钢纤维量应大于40 kg/m3.

Experimental study on mechanical properties of concrete with adding steel fiber at early age

In order to study the effect of steel fiber on the mechanical properties of concrete at early age,168 standard prisms were designed to test compressive strength and elastic modulus respectively,steel fiber volume percentage and age as parameters.By observing the failure pattern of the specimens,obtaining compressive strength and elastic modulus of concrete at early age,the effect of different steel fiber volume percentage on mechanical performances of concrete at early age were disclosed,equation of compressive strength-age and elastic modulus-age of concrete with adding steel fiber were deduced.The experimental results indicate that concrete with adding steel fiber,elastic modulus at early age was enhanced,but the improvement of compressive strength at early age was not obvious.Steel fiber volume percentage should be greater than 40 kg/m3 though the elastic modulus of 3 d and 28 d concrete was increased when the amount of admixture is more than 40 kg/m3.