Influence of Superplasticizer Dosage on Workability and Mechanical properties of Concrete made with Recycled Aggregate

Abstract

This study investigated the effect of adding a type of superplasticizer (polycarboxylate ether -PCE) on the workability and mechanical properties of concrete containing recycled coarse aggregate (RCA). The effect of increasing the PCE dosage while changing the water/cement ratio on RCA strength was also studied. To accomplish these goals, three groups of concrete mixtures were prepared. The variable in these groups was the water/cement ratio (0.53, 0.57, and 0.615). In each group, the natural aggregate was replaced by two proportions of RCA (50 and 100%) and different proportions of PCE were added for each replacement ratio. The findings encourage the use of PCE in recycled concrete. It was found that the addition of PCE improves the properties of recycled concrete in terms of workability and compactness. The addition of PCE also compensates for the compressive strength that is lost due to the replacement of natural aggregate with recycled coarse aggregate.

Preparation of a Polycarboxylate Superplasticizer with Different Monomer Regulations and Its Effect on Fluidity, Rheology, and Strength of Cement

“…12,13 Recent studies have focused on the mechanical improvement of PCE on cement, its static compressive and flexural strength tests have been widely conducted. 14,15 He et al proposed that organosilane-modified polycarboxylate (PCE) superplasticizers can accelerate the hydration rate and densify microstructures of cement, so the mechanical strength of cement with organosilane-modified PCE was increased compared with pure cement. 16 While cement materials are easily affected by the impact load in the application, the static test method is not comprehensive enough.…”

“…Therefore, the control of acid ether ratio is very important and is worth studying. Besides dispersing and water reducing effect in cement paste, PCEs can enhance the mechanical properties of cement because they can release the encapsulated water and improve the hydration degree. , Recent studies have focused on the mechanical improvement of PCE on cement, its static compressive and flexural strength tests have been widely conducted. , He et al proposed that organosilane-modified polycarboxylate (PCE) superplasticizers can accelerate the hydration rate and densify microstructures of cement, so the mechanical strength of cement with organosilane-modified PCE was increased compared with pure cement . While cement materials are easily affected by the impact load in the application, the static test method is not comprehensive enough.…”