土工格栅加筋透水混凝土力学性能试验研究

Experimental Study on Mechanical Properties of Geogrid Reinforced Pervious Concrete

研究了双向土工格栅的加筋位置及层数对透水混凝土孔隙率、透水系数、强度和弯曲性能的影响。研究表明:透水混凝土的有效孔隙率和透水系数随着格栅加筋层数的增加而增加,加筋后透水效果良好。加筋透水混凝土的强度较不加筋试样提高显著,抗压强度和抗折强度分别提高至26.3 MPa和3.9 MPa。将格栅设置在距离试样底部1/3h(h为试样高度)处时,抗压强度最高。在透水混凝土梁中加筋格栅后,混凝土梁有显著的开裂后性能,梁的破坏模式由脆性破坏变为延性破坏,梁的韧性提高,裂缝的发展被抑制,弯曲破坏有预兆性。加筋一层格栅时,距底部1/3h处是提高梁弯曲性能最有利的位置。加筋两层格栅的透水混凝土梁开裂后的延性优于加筋单层格栅的透水混凝土梁。同时在距离底部1/3h和2/3h处加筋格栅的透水混凝土梁弯曲性能最好。

This paper focuses on the influence of geogrid position and layer number on the effective porosity,permeability coefficient,strength and flexural behaviors of pervious concrete.Test results indicate that geogrid reinforced pervious concrete has excellent performances on drainage.Meanwhile,the effective porosity and permeability coefficient of pervious concrete increases with the increasing layer of embedded geogrid.Compared with the unreinforced pervious concrete,the compressive strength and flexural strength of reinforced pervious concrete increase to 26.3 MPa and 3.9 MPa,respectively.Embedding geogrid at one-third depth from the bottom of specimen can obtain optimal compressive strength of pervious concrete.In addition,geogrid reinforced pervious concrete beams have remarkable post-cracking performance.Using geogrid as reinforcement in pervious concrete beam improves the toughness to absorb more energy and restrain the generation and propagation of cracks.As a result,the damage form of beam is changed from brittle fracture to ductile fracture.Thus,the bending failure of the geogrid reinforced beam is predictable.One-third depth is the optimal position to improve the flexural behavior of pervious concrete beam when embedding one layer of geogrid.Pervious concrete beams reinforced with two layers of geogrids have better post-cracking performances than the cases reinforced with one layer of geogrid.Placing the geogrids at both one-third and two-thirds depth could obtain the optimal flexural behaviors.