Feasibility study of cement-stabilized materials using 100% mixed recycled aggregates from perspectives of mechanical properties and microstructure

Abstract

The research on the highly efficient reutilization of mixed recycled aggregates (MRA) produced from construction and demolition waste has attracted significant attention globally. In this study, the feasibility of using 100% MRA in cement-stabilized materials was investigated. The mechanical properties and microstructures of cement-stabilized MRA (CSMRA) materials containing 100% MRA were systematically examined through unconfined compressive strength (UCS) test, indirect tensile strength (ITS) test, drying shrinkage test, X-ray diffraction analysis, mercury intrusion porosimetry, and scanning electron microscopy. Results showed that the UCS and ITS of CSMRA materials were significantly enhanced with the increase of cement content and curing age, and there was almost a linear relationship between the UCS and ITS. The failure behavior of CSMRA materials under load showed three typical stages: compaction stage, elastic stage, and yield stage. The increase of the cement content caused the drying shrinkage deformation of CSMRA to increase sharply when the cement content exceeded 4%. The microstructural analysis indicated that cement had both filling and binding effects on CSMRA materials. The strength growth with cement content and curing age was because of the constant hydration of cement minerals, producing more calcium silicate hydrate binders between aggregates. Moreover, the increasing cement content could reduce the porosity and optimize the pore structure distribution of CSMRA materials. The findings of this study demonstrate that the use of 100% MRA in cement-stabilized materials as a road base is feasible, which will significantly enhance the utilization efficiency of MRA.

A Study on Mechanical and Microstructural Characteristics of Concrete Using Recycled Aggregate

“…The crushed C&DW particles are mainly composed of concrete, mortar, bricks, glass, and wood pieces and can be used as mixed coarse recycled aggregate (MCRA) [ 7 , 8 , 9 ]. The physical properties of MCRA are complex owing to its various components.…”

Study on the Construction Waste Composition and Strength Mechanism of Recycled Mixture

“…Due to the small particle size, the packing effect occurs, which reduces the overall porosity and optimizes the pore structure and the performance of the interfacial transition zone. Due to the small particle size, the packing effect occurs, which reduces the overall porosity and optimizes the pore structure and the performance of the interfacial transition zone [25][26][27][28][29][30][31][32]. Second, in the mixing process of the mixture, because there are many pores in RA, absorbing more water is conducive to the hydration process of the water-stable specimen in the health period, generating more cement hydration products and improving the cohesion of the mixture [29].…”

Laboratory Analysis of Recycled Cement Stabilized Concrete Aggregates as Subbase Materials

“…Recently, numerous laboratory studies and field trials have shown that recycled aggregate can totally or partially replace natural aggregates in road construction. Potential savings in cost and time of recycling of construction and demolition debris have made the use of RCA an attractive alternative to the highway engineer as it contributes to more sustainability in the construction [6]. Although many authors have studied the possibility of using RCA in applications, there are a few researches on the properties and mechanical behavior of mixtures treated with cement when used as road subbases or base in paving, roads because of these reasons: improving the workability of road materials, increasing the strength of the mixture, enhancing the durability, increasing the load spreading capacity.…”