Abstract
The paper describes the mechanical behavior of fine recycled concrete aggregate (FRCA) concrete according to the mineral admixtures. Three types of the mineral admixtures, i.e., fly ash (FA), ground-granulated blast-furnace slag (GGBS), and silica fume (SF), are used and the replacement ratios of FRCA are 50% and 100%. The dosages of the admixtures of FA, GGBS, and SF are determined with the normal dosage (30%, 40%, and 5.0%, respectively) based on the ACI committee reports (No. 232, 233, and 234) and half-normal dosage. The mechanical performance is investigated with the compressive and splitting tensile strength, and elastic modulus. Additionally, the total porosity is measured in natural fine aggregate (NFA) and FRCA 100% replaced specimens by mercury intrusion porosimetry (MIP) for investigating the relationship with the compressive strength. Based on the experimental test results, the mineral admixtures improve the mechanical performance of FRCA concrete. The effective dosages of FA, GGBS, and SF for FRCA concrete are investigated according to the replacement ratio of the FRCA. In particular, FRCA 100% replaced concrete may be possible to be used for the structural concrete members with the specific dosage of the mineral admixtures. The prediction of the splitting tensile strength and the elastic modulus by the codes or previous formulas exhibits underestimated and overestimated results, respectively. The relationship between the total porosity and the compressive strength of the FRCA concrete should be modified with more experimental tests.
Highlights
The depletion of natural aggregates in construction has been a significant reason to begin the use of substitutes, such as artificial aggregates, wastes, and recycled products
The purpose of this study is to investigate the mechanical performance of concrete with commercially produced fine recycled concrete aggregate (FRCA) employing the three types of the mineral admixtures, namely fly ash (FA), ground-granulated blast-furnace slag (GGBS), and silica fume (SF)
The study investigates the effect of the mineral admixtures on the mechanical performance of FRCA concrete, which includes the compressive strength, splitting tensile strength, and elastic modulus
Summary
The depletion of natural aggregates in construction has been a significant reason to begin the use of substitutes, such as artificial aggregates, wastes, and recycled products. One of the promising materials is the recycled concrete aggregate (RCA) from demolition of the concrete members [1,2]. This recycling process is familiar and practical achievement which can friendly feedback them in the construction field. The old cement paste on the surface of RCA can bring the adverse effects on material property. The FRCA concrete is more difficult to incorporate into the structural concrete than coarse recycled concrete aggregate (CRCA) concrete, mainly due to FRCA’s water absorption that result in workability issues with fresh concrete [5].
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