纤维改良建筑废料再生绿色混凝土工程性能研究

Investigation Engineering Performance of Recycled Green Concrete with Fiber Improved Construction Waste

为有效提升建筑废料再生绿色混凝土(RAC)的力学性能,室内利用钢纤维和聚丙烯纤维分别制备了钢纤维改良RAC、聚丙烯纤维改良RAC以及钢-聚丙烯纤维改良RAC,并对三种RAC材料开展了坍落度试验和力学试验。研究发现:(1)素RAC拌合物坍落度较高,可以达到168.87 mm;单掺或混掺钢纤维和聚丙烯纤维材料后RAC拌合物的坍落度显著降低,单掺1%钢纤维材料的混凝土拌合物坍落度为92.16 mm,单掺0.8%PF材料的RAC拌合物坍落度为108.95 mm。(2)单掺钢纤维后混凝土的承载能力明显增强,而聚丙烯纤维则会劣化RAC试件的承载能力,单掺聚丙烯纤维后RAC强度出现轻微降低。当钢纤维和PF材料的掺量较大时,RAC试件的立方体抗压强度又出现了明显的降低。(3)当聚丙烯或钢纤维掺量较低时,RAC试件的抗拉强度随另一种纤维材料掺量的增大逐渐增大;而当PF或钢纤维掺量较大时,RAC试件的抗拉强度则会出现减小的现象。研究成果为我国建筑废料的回收利用以及混凝土的改良提供了一定的借鉴作用。

To effectively improve the mechanical properties of recycled green concrete(RAC)from construction waste,steel fiber modified RAC,polypropylene fiber modified RAC and steel polypropylene fiber modified RAC were prepared by using steel fiber and polypropylene fiber respectively,and slump test and mechanical test were carried out on three RAC materials.It is found that:(1)The slump of plain RAC mixture is high,which can reach 168.87 mm;the slump of RAC mixture is significantly reduced after single or mixed with steel fiber and polypropylene fiber materials.The slump of concrete mixture with 1%steel fiber materials is 92.16 mm and that of Rac mixture with 0.8%pf materials is 108.95 mm.(2)After adding steel fiber alone,the bearing capacity of concrete is significantly enhanced,while polypropylene fiber will degrade the bearing capacity of RAC specimens,and the strength of RAC decreases slightly after adding polypropylene fiber alone.When the content of steel fiber and PF material is large,the cube compressive strength of RAC specimen decreases obviously.(3)When the content of polypropylene or steel fiber is low,the tensile strength of RAC specimen increases gradually with the increase of the content of another fiber material;when the content of PF or steel fiber is large,the tensile strength of RAC specimen will decrease.The research results provide a certain reference for the recycling of construction waste and the improvement of concrete in China.