Research And Preparation Of Recycled Aggregate Pervious Concrete

The water permeable concrete made of the recycled aggregate from construction waste can have several benefits. On the one hand, there will be benefit to make full use of recycled aggregate which has caused construction waste problem and to reduce the exploitation of natural aggregates so that energy resources can be saved. On the other hand, the effective use of permeable concrete can improve the ecological environment, creating a comfortable and harmonious traffic atmosphere. First of all, in this paper, the raw materials which have been used in this experiment and the test methods are introduced. Secondly, the studies of the basic performance, performance optimization, durability and road performance of recycled water permeable concrete are introduced. Finally, the main research conclusions of the paper are summarized and the future research is also discussed.In the process of studying the basic properties of recycled concrete, modified mix design method and design orthogonal test is needed. The basic performance of recycled concrete was studied by the method of range analysis and chromatography analysis. Among them, the influence factors include the size of aggregate, the design porosity and water cement ratio. Performance indicators include compressive strength, flexural strength, total porosity, effective porosity and permeability coefficient. After considering the above factors comprehensively, we can analyze the optimal experimental combination of recycled concrete. In short, the two factors of mechanical properties and permeability of the water permeable concrete made of the recycled aggregate from construction waste, are two containing factors for each other, need to be integrated.From the two angles of recycled aggregate quantity and paste modification, we can optimize the performance of recycled aggregate concrete. Under different levels of recycled aggregate content, the change regulations of compressive strength, flexural strength, effective porosity and permeability coefficient of recycled concrete are studied. After taking into account the compressive strength, flexural strength and water permeability coefficient of these three indicators of common interest, we can get that the reasonable content of recycled aggregate in recycled concrete is 30%. The modified test of recycled water permeable concrete can be carried out by using silica fume, reinforcing material and EVA emulsion as modified materials. While the mechanical properties of recycled aggregate concrete are greatly improved by the addition of silica fume compound admixture, it is necessary to strictly control the content of it, to ensure the water permeability performance in the controllable range. Besides, the compatibility of EVA emulsion and cement is poor.The durability of recycled water permeable concrete was studied by means of the freezing-thawing cycle test and the dry-wet alternate test. Factors in the experiment included the size of aggregate, the amount of recycled aggregate, the water cement ratio, the design porosity, the modification of composite materials and the modification of EVA emulsion. In the test, the indicators of the quality loss rate, the loss rate of the strength and the relative dynamic elastic modulus are required to be tested. The objective requirement is that the strength loss rate and the mass loss rate of the recycled water permeable concrete are required to meet the requirements of the frost resistance of the industry standard after experiencing 25 freezing-thawing cycles.The research of the water permeable concrete made of the recycled aggregate from construction waste is divided into two parts, which are the field placement and the precast paving. This paper mainly describes the research method of mix proportion design, plane geometry design and structure combination design, discusses the construction scheme and the daily maintenance measures of recycled concrete, and shows the overall effect of the laying of the cast-in-place and precast collocation. In the test, we give four key performance indicators as an authoritative test, the results are as follows:the values of compressive strength, flexural strength, effective porosity and permeability coefficient were 32.6 MPa,3.89 MPa,17.7%,3.2 mm/s, respectively. The average permeability coefficient is 4.58 mm/s, which meets the requirements of the industry standard.