Comprehensive Analysis of Stress-strain Relationships for Recycled Aggregate Concrete

Abstract

There is a growing demand of suitable substitute materials of concrete ingredients especially fine and coarse aggregates in order to achieve sustainable development in the era of rapid urbanisation. Therefore, the concrete making process by utilisation of aggregates that recycled from construction and demolition (C&D) debris has emerged as a primary objective for many government agencies. Consequently, the utilisation of recycled aggregate concrete (RAC) in structural applications become essential aspect. However, RAC can be employed in structural applications only if effective stress-strain relationship is available. The stress-strain models developed for natural aggregate concrete (NAC) are not fully suitable for RAC. Hence, the selection of good model which has precise prediction capacity plays a crucial role. Moreover, the stress-strain models provide the basis for the analysis and modern design procedures especially in FEA packages. In the present study, the stress-strain models for RAC have been selected from the literature and critically reviewed in order to evaluate their predictive efficacy. The test samples in the form of measured stress-strain relations-hips derived from literature have been compared with the predictions of each selected model. Besides the comparison of measured and predicted stress-strain profiles, the output of selected models in terms of normalized toughness and ductility index was assessed. The consistency of output of models are further evaluated by employing statistical tools such as coefficient of variance and root mean square error. The outcomes of the model in the form of polynomial expression was relatively more accurate to that of other counterparts.

Effect of Replacement Ratio on Torsional Behaviour of Recycled Aggregate Concrete Beams

“…The average of two beams is reported in Table 5. This result indicates slightly inferior than NAC, but considerable behaviour of RAC beam in torsion as found in the literature [2][3][4][5].…”

“…Because RAC has an inferior elastic modulus than NAC and the twist angle of beams at every loading state increases as the ratio of RCA was increased. Similar torsional behaviour was mentioned `in the experimental work [4,5]. Table 5 summarized data when RCA grows, the cracking torque to ultimate torque capacity decreases.…”

“…13.93 %, as shown in Table 3. In the majority of circumstances, it was expected that the mechanical qualities of RAC would be inferior to those of conventional concrete as found in the literature [4,5]. RAC with 100 % RCA had low mechanical properties because the aggregate-cement paste bond broke down.…”

“…According to Sarsam et al [4], the application of RCA in RAC is nearly conceivable in torsionally loaded structural elements. The analytical (ATENA-3D) and experimental study showed that altering RCA does not degrade pure torsional behaviour of RAC solid beams and the utilization of RAC in structural applications has become an essential aspect [5,6]. These studies demonstrated the significance of RAC beams in pure torsional design; as a result, this investigation explored the structural behaviour of RAC beams subjected to pure torsion.…”

Effect of Wastewater Curing and Elevated Temperature on Recycled Concrete Aggregates from Construction and Demolition Wastes

“…RAC beams have better performance than NAC beams, and they can be used as structural concrete [20]. The utilization of RAC in structural applications has become an essential aspect in recent studies [21]. The experimental examination of RAC beams demonstrated that altering the amount of RCA in RAC had no effect on structural behavior [22,23].…”