Experimental investigation of shear strength of concrete beams with recycled concrete aggregates

Alzahraa, Fatma; El-Mihilmy, Mahmoud T.; Bahaa, Tarek

doi:10.1504/ijmsi.2011.044418

Cited by 30 publications

(15 citation statements)

References 11 publications

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“…A comprehensive experimental database of RAC beams loaded in shear and their reference beams made with NAC was constructed in this study, as detailed in Appendix A Table A1 . This database comprised 264 datasets (206 beams without steel stirrups and 58 beams containing steel stirrups) collected from 28 published works across the world [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. Experimental outcomes published in Chinese [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ] were also included as a complement.…”

Section: Shear Test Database and Existing Prediction Methodsmentioning

confidence: 99%

“…Up to now, significant efforts have been made worldwide in response to the doubts just mentioned [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Early shear tests [ 18 , 19 , 20 ] indicated that RAC beams have similar cracking pattern and failure modes with those of NAC ones, but present lower diagonal cracking load and inferior shear-resisting capacity.…”

Section: Introductionmentioning

confidence: 99%

“…Early shear tests [ 18 , 19 , 20 ] indicated that RAC beams have similar cracking pattern and failure modes with those of NAC ones, but present lower diagonal cracking load and inferior shear-resisting capacity. From then on, interest has been sparked, providing more invaluable experimental evidence into this area [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. For example, Fathifazl et al [ 24 ], Arezoumandi et al [ 25 , 26 ], and Knaack and Kurama [ 27 ] investigated the effects of replacement level and longitudinal reinforcement ratio on the shear behavior of RAC beams.…”

Section: Introductionmentioning

confidence: 99%

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Machine Learning-Based Evaluation of Shear Capacity of Recycled Aggregate Concrete Beams

Yong

Zhao

et al. 2020

Materials

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Recycled aggregate concrete (RAC) is a promising solution to address the challenges raised by concrete production. However, the current lack of pertinent design rules has led to a hesitance to accept structural members made with RAC. It would entail even more difficulties when facing application scenarios where brittle failure is possible (e.g., beam in shear). In this paper, existing major shear design formulae established primarily for conventional concrete beams were assessed for RAC beams. Results showed that when applied to the shear test database compiled for RAC beams, those formulae provided only inaccurate estimations with surprisingly large scatter. To cope with this bias, machine learning (ML) techniques deemed as potential alternative predictors were resorted to. First, a Grey Relational Analysis (GRA) was carried out to rank the importance of the parameters that would affect the shear capacity of RAC beams. Then, two contemporary ML approaches, namely, the artificial neural network (ANN) and the random forest (RF), were leveraged to simulate the beams’ shear strength. It was found that both models produced even better predictions than the evaluated formulae. With this superiority, a parametric study was undertaken to observe the trends of how the parameters played roles in influencing the shear resistance of RAC beams. The findings indicated that, though less influential than the structural parameters such as shear span ratio, the effect of the replacement ratio of recycled aggregate (RA) was still significant. Nevertheless, the value of vc/(fc)1/2 (i.e., the shear contribution from RAC normalized with respect to the square root of its strength) predicted by the ML-based approaches appeared to be insignificantly affected by the replacement level. Given the existing inevitable large experimental scatter, more shear tests are certainly needed and, for safe application of RAC, using partial factors calibrated to consider the uncertainty is feasible when designing the shear strength of RAC beams. Some suggestions for future works are also given at the end of this paper.

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Section: Shear Test Database and Existing Prediction Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Machine Learning-Based Evaluation of Shear Capacity of Recycled Aggregate Concrete Beams

Yong

Zhao

et al. 2020

Materials

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“…The tests showed that the shear strength is reduced by up to 30% at 100% aggregate replacement ratio compared with the natural aggregate concrete. Al-Zahra et al [3] tested 12 beams with different percentage of recycled concrete aggregates, shear reinforcement and shear spans under two concentrated loads up to failure. Tests results demonstrated that the shear strength decreases with an increase in the coarse aggregate replacement ratio.…”

Section: Literature Searchmentioning

confidence: 99%

Shear Strength of Reinforced Concrete Beams Made with Recycled Aggregate

Tabsh¹,

Yehia²

2018

World Congress on Civil, Structural, and Environmental Engineering

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Using recycled concrete aggregate in new concrete mixes saves landfill space, reduces the need for gravel mining, and decreases pollution from transporting concrete to and from worksites. Recycled concrete aggregate may come from a variety of sources but the most common source is the demolition waste of old concrete structures. In this study, the recycled aggregate was obtained locally from Bee'ah's facility in Sharjah, UAE, and the percentage of coarse aggregate replacement in the concrete mix was either 50% or 100%, in addition to the control mix which included 100% natural aggregate. The target 28-day compressive strength based on 150mmx300mm cylinder was within the range 30-35MPa. The first phase of the study addressed the recycled aggregate tests and concrete mix design while the second phase involved shear strength of three half-scale reinforced concrete beams made with the recycled and natural aggregate. In the later part, the simply supported beams were tested under a single-point loading scheme inside a Universal Test Machine at a shear span-to-depth ratio of 1.5 to determine the load-deflection performance up to failure. Results of the study showed that the elastic stiffness, ultimate shear capacity and residual strength of steel reinforced beams made with 50% and 100% recycled coarse aggregate were comparable to those made entirely with natural aggregate and can be conservatively predicted by the theoretical equations of the ACI 318 code.

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“…Effect of using RCA on the mechanical properties of RC beams was studied by many researchers (Arezoumandi et al, 2015; Al-Zahraa et al, 2010; Ignjatović et al, 2013; Knaack et al, 2014; Maruyama et al, 2004). Each of these studies assessed the strength and serviceability of a set of beams with conventional and recycled concrete.…”

Section: Introduction and Research Significancementioning

confidence: 99%

Effect of recycled coarse aggregate on physical and mechanical properties of concrete

Elansary

Ashmawy

Abdalla

2020

Advances in Structural Engineering

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Recycling of building waste has become essential process in the construction industry due to the sustainability and economic benefits such as decreasing the waste to landfill, conserving natural resources, and reducing pollution. Large amount of building waste is produced from the construction and demolition process of reinforced concrete (RC) structures. In this paper, the effect of using recycled coarse aggregate (RCA) on the behavior of concrete is experimentally studied. The RCA is prepared by crushing and sieving of waste of standard compression test cubes having a compressive strength ranging between 25 MPa and 30 MPa. The physical and mechanical properties of RCA are experimentally estimated and compared to those of natural coarse aggregate (NCA). A set of 72 standard concrete cubes, cylinders, and beams specimens are made using coarse aggregate replacement ratios (CARR) of 0%, 30%, 50%, and 100%. The specimens are tested to estimate the compressive, splitting, and flexure strengthens at the ages of 7 and 28 days. The study is extended by using the RCA in casting 12 RC columns with CARR similar to those of specimens. The columns are tested in an axial compression test protocol till failure. Crack patterns, failure loads, strains, displacements, and toughness of the tested columns are compared. It is concluded that using a CARR of 30% and 50% and a specific water cement ratio provides better mechanical behavior than that of NCA while the CARR of 100% yields worst mechanical behavior compared to that of NCA.

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Experimental investigation of shear strength of concrete beams with recycled concrete aggregates

Cited by 30 publications

References 11 publications

Machine Learning-Based Evaluation of Shear Capacity of Recycled Aggregate Concrete Beams

Machine Learning-Based Evaluation of Shear Capacity of Recycled Aggregate Concrete Beams

Shear Strength of Reinforced Concrete Beams Made with Recycled Aggregate

Effect of recycled coarse aggregate on physical and mechanical properties of concrete

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