Research On Utilization Of Urban Construction To Prepare The Premeable Pavement Materials

With the rapid development of economy of China and the dramatic increase in population,the construction waste generated by industry and human survival has been increasing.At the same time,problems such as environmental deterioration,ecological destruction,and severe shortage of resources have become increasingly acute.In China,The Most of the disposal methods for construction waste are landfill disposal.This treatment method will cause direct pollution and potential hidden dangers to the environment.At the same time,the urbanization process will also affect the ecological environment.The huge damage caused by the impervious pavements used in urbanization,which has had a major impact on the water cycle in city.The purpose of this paper is to use the construction waste to prepare the pervious paving bricks.On the one hand,it is the way to resource utilization the solid waste,on the other hand it helps to make efforts to build the“sponge city”.This article selects the construction waste that is suitable for use as a pervious paving block,and analyzes the impact of water-cement ratio,target porosity,fly ash content,and husk ash content on pervious paving blocks.In the meanwhile,using physical reinforcement and the chemical strengthening to keep balances between the mechanical properties and the permeability coefficient of the pervious paving bricks.The specific work is as follows:?1?Construction waste was broken into two kinds of particle size of 2.5⁵mm and5mm¹0mm,whichare used to prepare the pervious pavement brick with the base layer and the surface layer composite structure.The particle size of 2.5⁵mm is used for pervious pavement brick layer,and the particle size of 5mm¹0mm is used for pervious pavement brick base layer.The physical properties parameters of these two particle sizes have been tested respectively,and the apparent density and accumulation of the two particle sizes are obtained.?2?Using the volume method and L₉?3⁴?orthogonal table to design the mix ratio of pervious paving bricks and using the range and trend line to analyze the orthogonal test results,which affect the compressive strength and flexural strength.The primary and secondary order of factors is as follow:It is the factors that affecting the permeability coefficient:the ratio of water to cement,the target porosity,the content of rice husk ash,and the content of fly ash.The factors affecting the permeability coefficient are primary and secondary target porosity>water-cement ratio>fly ash Amount>rice husk ash content.The optimal scheme of data:water-cement ratio is 0.3,target porosity is 15%,fly ash content is 10%,and rice husk ash is content 15%.?3?The strengthening effect of the permeable pavement brick have been discussed from two aspects of physical and chemical strengthening.The method of physical reinforcement is to select the suitable static pressure and appropriate sisal incorporation.The range of suitable static pressure is:2.5MPa³.5MPa,when the sisal content is 1%of the cementitious material,the perforated paving brick has the best mechanical properties.Chemical strengthening is to promote the hydration reaction of cement by adding fly ash and rice hull ash to strengthen the pervious paving bricks.Orthogonal results show that when the fly ash and rice husk ash are 15%and 10%of the cementitious material respectively,the perforated pavers have the best mechanical properties and water permeability.?4?The mechanism of hydration reaction of cement was discussed.The SEM microanalysis and X-ray diffraction analysis of aggregate,fly ash and rice husk ash were carried out.