Full-component Of Waste Cement Andutilization Of Recycled Concrete

Abandoned concrete is a large amount of solid waste continuously generated during the use,maintenance and demolition of buildings,and its resource utilization has been receiving much attention.In order to accelerate the construction of ecological civilization and build an environment-friendly society,it is a general trend to apply waste concrete,a large building product waste,to civil engineering.In this paper,waste concrete is used as the main raw material.Through the selection of the particle size of the crusher outlet,the crushing method suitable for the aggregate gradation particle size and the most compact accumulation of aggregate is found,and the resource utilization of the waste concrete components is realized.This paper conducts major research in the following areas:(1)Preparation of the most compact size graded recycled aggregateIn order to prepare the recycled aggregates that meet the closest packing grading,by controlling the different discharge apertures of the crushing device,comparing the relationship between the grading of the recycled aggregate and the standard grading curve,it is proposed to satisfy the aggregate grading and compact packing.Density breaking method.The results show that there are few mortar blocks and aggregates on the surface of the recycled coarse aggregate produced by the 2.36mm and 1.18mm discharge pore size crushing,and the gradation of the recycled aggregate can meet the requirements of the sand in Zone Ⅱ.It can be used as aggregate of recycled concrete.(2)Effect of regenerated fine powder on the performance of gelling systemIn order to investigate the effect of regenerated fine powder on the performance of the gelling system,the grinding time(specific surface area)of the suitable regenerated fine powder was determined by comparing the regenerated fine powders at different grinding times.The appropriate amount of the regenerated fine powder is determined by analyzing the regenerated fine powder stability,the standard consistency water consumption,the setting time,the compatibility with the water reducing agent,and the mechanical strength of the preferred surface area.In the comparison of the activity index of the reclaimed mortar,a chemical activator suitable for the amount and type is selected.The results show that the specific surface area of the regenerated fine powder does not increase greatly with the increase of the grinding time,and the optimum grinding time is 60 min(specific surface area:400 m2/kg).The amount of the regenerated fine powder incorporated as a gelling material is 30%or less,which can satisfy the stability requirement.With the increase of the amount of recycled fine powder,the water consumption and the setting time of the standard consistency of the gelling system are correspondingly increased,and the saturated dosage of the water reducing agent is also increased correspondingly under the same fluidity,which promotes the particle size distribution of the whole gelling system.The greater the amount of recycled fine powder,the lower the mechanical properties of the gelling system.The use of 5%Na2SO4 solution as an activator is more advantageous for the strength of the regenerated micronized gelling system.(3)Experimental study on the performance of hardened cement stone by coal gangue.In order to stimulate the activity of the regenerated micropowder,the method of modifying it with coal gangue was explored.The research on the pre-and post-development laws of the modified cement stone determined the recent modified cement stone content.The results show that the non-self-igniting coal gangue has a good grinding effect on the hardened cement stone.When the dosage is 30%and the grinding time is 35min,the grinding effect is best.When the gangue modified dehydrated cement stone is used as the mixed material.When the calcined at 600℃,the cement stone has better gelation,but the early strength is high and the late strength is low.When the coal gangue content is 30%and the calcination temperature is 800℃,the obtained calcined cement stone is the best modification.The paper has 29 figures,23 tables and 94 references.