Capillary Water Absorption Characteristics of Recycled Concrete in Freeze-Thaw Environment

Qianhui Xiao,Jisheng Qiu,Yangyang Li,Xiaolin Liu

doi:10.1155/2020/1620914

Abstract

In order to study the capillary water absorption characteristics of recycled concrete (RAC) with different replacement rates of recycled coarse aggregate (0, 20%, 40%, and 60%) in freeze-thaw environment, the standard test method of measuring the water absorption of hydraulic cement concrete (ASTM C1585-13) was adopted, and the influence mechanism of freeze-thaw cycle and replacement rate of recycled coarse aggregate on the capillary water absorption of RAC was analyzed, and a prediction model of initial capillary water absorption of RAC in freeze-thaw environment was established. The results show that when the freeze-thaw environment is the same, the greater the replacement rate of recycled coarse aggregate, the greater the cumulative water absorption of RAC, the faster the initial capillary water absorption, and the stronger the capillary water absorption; when the freeze-thaw environment is different, the more the freeze-thaw cycles, the greater the cumulative water absorption of RAC with the same replacement rate of recycled coarse aggregate, the faster the initial capillary water absorption, and the stronger the capillary water absorption. The prediction model of RAC initial capillary water absorption established by regression analysis has high accuracy, which can be used to predict RAC capillary water absorption performance and provide theoretical basis for the research of RAC frost resistance durability.

Highlights

Since the reform and opening up, China’s economy has continued to develop at a high speed, and the construction industry as a pillar industry has made great achievements
The use of concrete in China accounts for 45% of the total use in the world, and it is estimated that the output of domestic construction waste will reach an amazing 3.966 billion tons by 2020
It has been studied that a large number of waste mussel shells from aquaculture and mussel factory residues are partially or completely replaced by natural aggregate to prepare recycled concrete for engineering application, which improves the sustainability of this new type of concrete and the environment [2]

Summary

Introduction

Since the reform and opening up, China’s economy has continued to develop at a high speed, and the construction industry as a pillar industry has made great achievements. It has been studied that a large number of waste mussel shells from aquaculture and mussel factory residues are partially or completely replaced by natural aggregate to prepare recycled concrete for engineering application, which improves the sustainability of this new type of concrete and the environment [2]. E application of recycled concrete technology will form the circular industry development mode of “production-usewaste-reproduction-use of concrete, which can realize the effective recycling and reuse of waste concrete. It is of great significance for environmental protection, resource. Erefore, it is necessary to study the capillary water absorption performance of recycled concrete in freeze-thaw environment. Based on the capillary water absorption test and freezethaw cycle test, this paper studies the effect of freeze-thaw cycle and recycled coarse aggregate replacement rate on the capillary water absorption of recycled concrete, analyzes the initial capillary water absorption of recycled concrete in different freeze-thaw environments, and establishes the prediction model of the initial capillary water absorption of recycled concrete in the freeze-thaw environment, so as to improve the capillary water absorption of recycled concrete for reference

Experiment

Test Method

Results and Discussion

Conclusion