纳米粒子和钢纤维增强混凝土断裂能研究

Experimental study on fracture energy of fiber and nano-particle reinforced concrete

为了研究纳米Si O2、钢纤维和预切口小梁试件相对裂缝深度对钢纤维增强纳米混凝土断裂韧性的影响,通过三点弯曲试件断裂试验,测得了试件的断裂能以及竖向荷载与裂缝嘴张开位移和裂缝尖端张开位移的关系曲线。试验结果表明:钢纤维和纳米Si O2在一定掺量范围内可使混凝土的断裂能提高;当纳米Si O2掺量小于5%时,试件断裂能随着纳米粒子掺量的增加而逐渐增大,而当纳米Si O2掺量超过5%后,试件断裂能随纳米粒子用量增大而逐渐下降;掺纳米粒子混凝土的断裂能随着钢纤维体积掺量的增加逐渐增大,当纤维体积掺量超过2%后又逐渐减小;三点弯曲断裂小梁试件相对切口深度对断裂能有较大影响,随着相对切口深度的增大,试件断裂能逐渐减小。

Experimental tests on three-point bending fracture of steel fiber and nano-particle reinforced concrete is conducted to study the effect of nano-particles, steel fibers and relative notch depth on its fracture toughness, focusing on the measurements of fracture energy and fracture process. The test results indicate that adding appropriate contents of nano-Si O2 and steel fibers to the concrete can improve its fracture energy significantly. As the nano-Si O2 content is increasing, fracture energy is increased gradually up to a peak content of 5% and then decreased gradually. And with the increasing steel fiber content, it manifests a similar tendency and has a peak value at the content of 2%. The depth of a relative notch on a beam specimen has great effect on its fracture energy that is decreased gradually with the increasing depth.