黄河砂制备再生混凝土的界面增强方法研究

Research on Interface Strengthening Method for Preparing Recycled Concrete from Yellow River Sand

黄河泥砂淤积及沿线旧建筑拆除是黄河流域生态保护亟待解决的工程问题,开展黄河砂与再生骨料协同制备再生混凝土是实现节能减排的途径之一,然而黄河砂表面与水化硅酸钙的联结薄弱是关键制约因素。基于此,采用硅烷偶联剂、草酸、防水砂浆和聚乙烯醇对黄河砂进行界面增强处理,通过力学性能和界面微观形貌测试,分析了这些增强方法对再生混凝土宏观力学性能的影响,并研究了不同界面增强方法对黄河砂-水化硅酸钙界面联结的微观增强效果,同时探讨了黄河砂与建筑固废协同制备再生混凝土的技术经济性。结果表明,上述界面增强方法对再生混凝土的界面强度提升效果为硅烷偶联剂>聚乙烯醇>防水砂浆>草酸;掺加10%硅烷偶联剂与10%聚乙烯醇可分别提升混凝土的抗压强度23.5%和11.8%,并具备良好的施工和易性;黄河砂与建筑固废协同制备市政工程非承重再生混凝土结构具有显著的生态效益,并具备较好的经济性。

The sedimentation of Yellow River sand and the demolition of old buildings along the Yellow River Basin are urgent engineering problems that need to be solved for ecological protection in the Yellow River Basin.That the collaborative preparation of recycled concrete from Yellow River sand and recycled aggregates is one of the ways to achieve energy conservation and emission reduction.However,the weak connection between the surface of Yellow River sand and hydrated calcium silicate is a key limiting factor.Based on this,Silane coupling agent,Oxalic acid,waterproof mortar,and polyvinyl alcohol were used to enhance process of the interface of Yellow River sand.Through mechanical properties and interface microstructure testing,the effect of these strengthening methods on the macroscopic mechanical properties of recycled concrete was analyzed,and the micro strengthening effect of different interface strengthening methods on the interface connection between Yellow River sand and hydrated calcium silicate was studied.At the same time,the technical and economic benefits of the synergistic preparation of recycled concrete with Yellow River sand and building waste were discussed.The results show that the interface strength improvement effect of the above interface reinforcement methods on recycled concrete is silane coupling agent>polyvinyl alco-hol>waterproof mortar>oxalic acid;The compressive strength of concrete can be increased by 23.5%and 11.8%,respectively by adding 10%silane coupling agent and 10%polyvinyl alcohol,and have good workability for con-struction;The synergistic preparation of municipal engineering non load-bearing recycled concrete structures by Yellow River sand and construction solid waste has significant ecological and economic benefits.