Effect of fine recycled aggregate on the strength and durability properties of concrete modified through two-stage mixing approach

Abstract

To overcome the scarcity of river sand and dumping of construction and demolition wastes, the fine recycled aggregate (FRA) collected from C&D wastes is being utilized as a replacement to river sand. Many earlier studies reported that the higher water absorption of fine recycled aggregate and weak interfacial transition zone (ITZ) resulted in the development of the concrete with less strength and durability requirements. This study surmounts the above two factors through pre-saturation and a two-stage mixing approach (TSMA) technique. The concrete mixes prepared at 0.45 w/c ratios with 0%, 25%, 50%, and 100% of FRA were evaluated through hardened properties such as compressive strength, split tensile strength, flexural strength, and durability properties such as water absorption, sorptivity, shrinkage, rapid chloride penetration, and carbonation tests. The results indicate that the optimum level of replacement of fine recycled aggregate was 25% and the increase of fine recycled aggregate decreases the strength and durability properties. However, increased curing of concrete resulted in better strength and durability properties. The strength of the concrete was increased by 12% at 28 days and 17.46% at 90 days by two-stage mixing approach. The water absorption, porosity, shrinkage, chloride penetration, and carbonation of two-stage mixing approach was decreased by 7.45%, 15.38%, 16.57%, 18.18%, and 13.51% compared to normal mixing approach. Microstructural investigations show improvement in the interfacial transition zone with two-stage mixing approach compared to normal mixing approach.

A Comprehensive Review of Stone Dust in Concrete: Mechanical Behavior, Durability, and Environmental Performance

“…Regarding the percentage of substitution by stone dust, the permeability for chloride ions increases with the increase in the SD percentage. In general, it can be seen that with 0% of SD, electric flux is around 1260 C [40,86,127,130]; with 25% of SD substitution this value rises to 1713 C [40,130], with 50% it rises to 2033 C [127,130], and with 100%, it is 4000 C [130]. According to ASTM C1202 [129], electric flux in the range of 2000-4000 C is classified as moderate ion permeability.…”

The Durability of Recycled Fine Aggregate Concrete: A Review

“…RFA is one of the important reasons for the performance of concrete due to its excessive water absorption; however, the use of moisture in the two-part addition, i.e., the two-stage mixing method (TSMA), can effectively prevent the excessive water absorption of RFA [ 68 ]. The performance of concrete with different RFA replacement rates prepared by the normal mixing method and TSMA was investigated, and it was found that the drying shrinkage values of all RFAc using TSMA were lower than those of the concrete prepared by the normal mixing method, mainly because of the higher compactness and better ITZ of RFAc prepared by TSMA [ 69 ].…”

Compressive Performance of Fiber Reinforced Recycled Aggregate Concrete by Basalt Fiber Reinforced Polymer-Polyvinyl Chloride Composite Jackets

“…The compressive behavior of the cylinder under uniaxial compressive tests was studied. As is well known, the stress-strain relationship of the structural member was essential for compressive behavior [27][28][29][30]. For instance, Chang et al [31] investigated the effect of the recycled aggregate (RA) replacement ratio on the stressstrain behavior of different concrete strengths.…”