Mechanical Properties of Large Slump Concrete Made by Post-Filling Coarse Aggregate Mixing Procedure

Abstract

High-performance pumping concrete has been widely used in high-rise building construction because of its superior qualities. However, early cracking problems can occur in cast-in-place pumping concrete, which is due to the excessive use of cement. In this paper, an innovative concrete mixing procedure called “post-filling coarse aggregate concrete” (PFCC) was adopted and applied to large slump concrete. The influence of the post-filling coarse aggregate (PFA) ratio on the mechanical properties of large slump concrete were investigated. Three different concrete strength grades (C30, C40 and C50) and five different PFA ratios (0%, 10%, 15%, 20%, 25%) were considered. The designed slump for the reference concrete was 180–200 mm. Experimental tests on the compressive strength of cubic specimens, axial compressive strength of prism specimens, splitting tensile strength, modulus of rupture and modulus of elasticity were performed. All tests were conducted in room conditions. Results showed that the slump of the PFCC decreases as the PFA ratio increases. It also indicated that, in general, the mechanical properties of PFCC are not linearly increasing as the PFA ratio rises, and there exists a turning point. Based on the experimental investigation and analysis in this study, the optimum post-filling coarse aggregate ratio is recommended to be 20%.

Shear Behavior of Reinforced Post-Filling Coarse Aggregate Concrete Beams Produced by Creative Construction Process

“…The stirrup reinforcement ratio exhibits a noticeable influence on the enhancement of the ultimate shear capacity of the beam. (5) The code GB50010 provides conservative predictions for ultimate shear capacities V u for all tested beam specimens.…”

“…Originally used for pavement concrete, PFCC is used to solve the problem of aggregate suspension [4] and excessive paste of high-performance concrete, which is critical in meeting the working performance requirement. The post-filling coarse aggregate concrete not only reduces the use of cement [5] but also increases the volume percentage of coarse aggregates, which improves the early-age cracking resistance of concrete [6]. In practical application, it has been found that the strength properties [5] of concrete can also be improved.…”

“…The post-filling coarse aggregate concrete not only reduces the use of cement [5] but also increases the volume percentage of coarse aggregates, which improves the early-age cracking resistance of concrete [6]. In practical application, it has been found that the strength properties [5] of concrete can also be improved. Therefore, the method of post-filling coarse aggregate has a significant effect in reducing concrete cost, reducing shrinkage cracking and increasing compressive strength.…”

“…The technology of post-filling coarse aggregate concrete could reduce cement production and decrease carbon emissions. Furthermore, the compressive strength, elastic modulus and load-carrying capacity of columns of post-filling coarse aggregate concrete were also found to be improved [5,21,22]. The post-filling coarse aggregate ratio (PFR) is the volume fraction of the coarse aggregate in the total volume of the post-filling coarse aggregate concrete.…”

Flexural performance of reinforced concrete beams made by innovative post-filling coarse aggregate process

“…So far, investigations of post-filling coarse aggregate concrete on the structural element in building and bridge engineering have rarely been reported. Jia’s research group has carried out some experimental and theoretical research on the post-filling coarse aggregate concrete (Cao et al, 2020; Hu, 2015; Jia et al, 2017, 2020). It was found that the compressive strength, splitting tensile strength, elastic modulus and flexural strength of the post-filling coarse aggregate concrete with proper post-filling ratio have been improved compared with the reference concrete.…”