Zeng Yusheng, Zhou Xianyu, Tang Aiping, Sun Peng
School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China.
Key Lab of Structures Dynamic Behaviour and Control of the Ministry of Education, Harbin Institute of Technology, Harbin 150090, China.
Materials (Basel). 2020 Apr 6;13(7):1715. doi: 10.3390/ma13071715.
In this study, an experimental investigation was conducted on the mechanical properties of lightweight aggregate concrete (LWAC) with different chopped fibers, including basalt fiber (BF) and polyacrylonitrile fiber (PANF). The LWAC performance was studied in regard to compressive strength, splitting tensile strength and shear strength at age of 28 days. In addition, the oven-dried density and water absorption were measured as well to confirm whether the specimens match the requirement of standard. In total, seven different mixture groups were designed and approximately 104 LWAC samples were tested. The test results showed that the oven-dried densities of the LWAC mixtures were in range of 1.819-1.844 t/m which satisfied the definition of LWAC by Chinese Standard. Additionally, water absorption decreased with the increasing of fiber content. The development tendency of the specific strength of LWAC was the same as that of the cube compressive strength. The addition of fibers had a significant effect on reducing water absorption. Adding BF and PANF into concrete had a relatively slight impact on the compressive strength but had an obvious effect on splitting tensile strength, flexural strength and shear strength enhancement, respectively. In that regard, a 1.5% fiber volume fraction of BF and PANF showed the maximum increase in strength. The use of BF and PANF could change the failure morphologies of splitting tensile and flexural destruction but almost had slight impact on the shear failure morphology. The strength enhancement parameter was proposed to quantify the improvement effect of fibers on cube compressive strength, splitting tensile strength, flexural strength and shear strength, respectively. And the calculation results showed good agreement with test value.
在本研究中，对含有不同短切纤维（包括玄武岩纤维（BF）和聚丙烯腈纤维（PANF））的轻骨料混凝土（LWAC）的力学性能进行了试验研究。研究了LWAC在28天龄期时的抗压强度、劈裂抗拉强度和抗剪强度性能。此外，还测量了烘干密度和吸水率，以确认试件是否符合标准要求。总共设计了七个不同的混合料组，测试了约104个LWAC样品。试验结果表明，LWAC混合料的烘干密度在1.819 - 1.844t/m范围内，满足中国标准对LWAC的定义。此外，吸水率随纤维含量的增加而降低。LWAC比强度的发展趋势与立方体抗压强度相同。纤维的添加对降低吸水率有显著影响。向混凝土中添加BF和PANF对抗压强度的影响相对较小，但分别对劈裂抗拉强度、抗弯强度和抗剪强度的提高有明显效果。在这方面，BF和PANF纤维体积分数为1.5%时强度增加最大。BF和PANF的使用可以改变劈裂拉伸和弯曲破坏的破坏形态，但对剪切破坏形态几乎没有影响。提出了强度增强参数分别量化纤维对立方体抗压强度、劈裂抗拉强度、抗弯强度和抗剪强度的改善效果。计算结果与试验值吻合良好。
