Experimental Study On Compression Strength And Carbonation Property Of Recycled Concrete With Artificial Sand

The recycled aggregate concrete with artificial sand (RCAS), which is composed of artificial sand and recycled coarse aggregate, help relieve the growing shortage of natural sand and effectively deal with the environmental problems caused by waste concrete, which mean the RCAS is green and sustainable. Inevitably, there is a large number of stone powder in the artificial sand, which makes the RCAS has it’s different performance in all aspects compared with ordinary one. Thus, based on the theoretical and experimental results already achieved by the same research group, this paper makes further research on the influence of powder on the compressive strength and carbonation property, which can provide scientific basis for popularization and application of RCAS.In this study, four strength grades (C25, C30, C35, C40) were tested, and each strength grade consist of groups of RCAS with different stone powder content (0%,5%,7.5%,10%,12.5%,15%,20%) and a group of recycled aggregate concrete with natural sand (RCNS). Each group contained three cubes specimens (150mm×150mm×150mm) and three cylinder specimens (100mm×100mm×300mm). The paper study demonstrated the relation model among compressive strength of RCAS, C/W ratio and stone powder content. A semi-theoretical and semi-empirical prediction model is also got to analyse carbonation depth of RCAS. Main conclusions can be drawn as follows:1. With the increase of the stone powder content, compressive strength of RCAS increase first and then decrease. High strength grade RCAS’s compressive strength have high impact and fluctuations which caused by stone powder content, and the corresponding optimal stone powder content of its peak compressive strength is larger.2. Carbonation depth of RCAS increases as the growth of the carbonization time and water cement ratio, and the higer water cement ratio, the greater growth rate. Stone powder content have fluctuating effection on carbonation depth, and higher level content corresponds to smaller carbonation depth.3. With the increase of carbonization time,carbonation rate in RCAS and its reduce rate decreases, along with the change of stone powder content carbonation rate showed significant volatility, but the optimalstone powder contents for minimum rate and minimum carbonation depth are the same.4. In the same strength grade, compressive strength of RCAS is slightly higher than it in natural sand recycled concrete, but the effects on carbonization resistance caused by carbonization time and water cement ratio are similarity, except the demarcation points of carbonization time when fast carbonation rate turned into slow are different.