基于裹浆技术的废弃混凝土粒料性能增强研究

Research on Performance Enhancement of Waste Concrete Aggregate Based on Wrap Slurry Technology

为提高废弃混凝土粒料的性能,利用裹浆材料包裹废弃混凝土再生粒料(简称裹浆粒料)。采用不同浆体材料渗入废弃混凝土粒料的孔隙而产生填充作用,或与粒料中某些成分产生反应生成物以填充孔隙,并将再生粒料的微裂缝修补粘合,以改善再生粒料的棱角效应并强化再生粒料表面结构及孔隙结构,从而提升再生粒料的品质与特性。探讨了裹浆材料及裹浆量对裹浆粒料相对密度、吸水率、坚固性、洛杉矶磨损率及压碎值等宏观力学特性及微观特性的影响,同时利用灰关联分析评选出裹浆粒料的最佳方案。研究结果表明:裹浆粒料因表面附着一层致密的裹浆材料,具有修补废弃混凝土再生粒料表面微裂缝及补强再生粒料表面强度的效果,从而提高再生粒料抗压与抗磨损的能力;通过灰关联分析推荐最佳浆质材料为矿渣水泥浆,最佳裹浆厚度为0.25mm,沥青混合料的初步试验结果也验证了方案的可行性;采用最佳裹浆粒料取代25%的天然粗粒料沥青混凝土能够满足中国《公路沥青路面施工技术规范》的要求。

In order to enhance the performance of waste concrete aggregate, slurry material wrapped waste concrete recycled aggregates （referred to wrap pulp pellets） were adopted. Different kinds of slurry materials were used to penetrate into voids of waste concrete aggregates for filling or reacting with some ingredients of waste concrete to fill voids and repair micro-crack of recycled concrete. The mentioned method was used to improve the edge effect of recycled aggregates and enhance the performance of surface and pore structure of recycled concrete so as to improve the quality and characteristics of recycled concrete. The effects of warp pulp material and the warp pulp amount on macro-mechanical properties of relative density, water absorption, soundness, Los Angeles wear rate and crushing value and some other micro-properties were discussed. The method of gray relational analysis （GRA） was presented to determine the optimal scheme for warp pulp pellets. The results show that as one layer of intrinsically prepared compact pre-coating material is attached on the warp pulp pellets, it is capable of patching the tiny cracks on the surface of the recycled aggregate and reinforcing the surface strength of the recycled aggregate so as to improve the ability of recycled aggregate in resisting crushing and wearing.The optimal slurry material of slag cement slurry could be recommended by the grey relational analysis with the optimal coating thickness of 0. 25 mm. The primary test results of asphalt mixtures verify the validity of the scheme. Using optimal wrap pulp pellets to replace 25% natural coarse aggregate of asphalt concrete can meet the requirement of Specifications for Construction of Highway Asphalt Pavements of China.