Influence of Recycled High-Performance Aggregate on Deformation and Load-Carrying Capacity of Reinforced Concrete Beams

Abstract

The use of recycled concrete aggregates (RCA) in high performance concrete (HPC) was analyzed. The paper presents the experimental studies of model reinforced concrete beams with a rectangular section using high-performance recycled aggregates. Two variable contents of recycled aggregate concrete were used in this study: 50% and 100%. The experimental analyses conducted as immediate studies concerned the following issues: short time loads-deflection, load-carrying capacity of beams, deformation of concrete, cracks, and long-term loads-deflection. The comparative analysis involves the behavior of beams made of high performance concrete-high strength concrete (HPC-HSC) recycled aggregates with model control elements made of regular concrete based on natural aggregates. The deflection values for the recycled aggregate beams were 20% higher than in the case of the control beams made of HPC-HSC exclusively. Replacement of aggregate with recycled concrete aggregate resulted in a large decrease in the value of these two parameters, i.e., compression strength by about 42% and modulus of elasticity by about 33%.

Sustainable Recycling of High-Strength Concrete as an Alternative to Natural Aggregates in Building Structures

“…The graph clearly shows close correlation between the modulus of elasticity and the compressive strength of concrete. This is also confirmed by the previous studies conducted by the authors [30]. Similar conclusions were also drawn by Góra et al [52].…”

“…The chemical composition of the aggregates is presented in Table 4. The data have been taken from a paper published by one of the authors [30].…”

Properties of Concrete with Recycled Concrete Aggregate Containing Metallurgical Sludge Waste

“…Similar relationships were found for mortars containing 25%-100% fine RCA [28]. Reduction of compressive and flexural strength and elasticity modulus was also described for HPC containing RCA after 7, 14 and 28 days [26]. Concretes containing 50% and 100% RCA have lower compressive strength compared to control concrete, however, the use of concrete from railway sleepers demolition caused an increase in strength [25].…”

“…The absorbability increases from about 5.5% for concrete without RCA to about 8% at 100% replacement level. Increase of absorbability and porosity by 15%-38% and decrease of density by 4%-7% for HPC is described in [26]. Studies described in [25] showed that concretes containing 50 and 100% RCA have a lower density compared to control concrete.…”

“…The full replacement of the natural aggregate with RCA results in a lower concrete mix density [23]. The density of High Performance Concrete (HPC) containing RCA is lower compared to the control mix [26]. The tests described in [25] showed that mixtures containing 50% and 100% RCA have lower density in comparison with the control mixture.…”