A database on flexural and shear strength of reinforced recycled aggregate concrete beams and comparison to Eurocode 2 predictions

Tošić, Nikola; Marinković, Snežana; Ignjatović, Ivan

doi:10.1016/j.conbuildmat.2016.10.058

Cited by 56 publications

(20 citation statements)

References 35 publications

(69 reference statements)

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“…Based on the literatures reported [37], more researches on shear performance of reinforced recycled aggregate concrete beams without web reinforcement have been carried out and evaluated with the current design codes. Comparatively, less studies were performed on the shear behavior of reinforced recycled aggregate concrete beams with stirrups, thus further researches and experimental results are necessary.…”

Section: Research Significancementioning

confidence: 99%

Shear Performance of Reinforced Concrete Beams Affected by Satisfactory Composite-Recycled Aggregates

Liang

Zhao

et al. 2020

Materials

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This paper is the outcome of experiments on the shear performance of reinforced concrete beams with approved composite-recycled aggregates. The strength grade of composite-recycled aggregate concrete (CRAC) was between 30 MPa and 60 MPa. The shear span-to-depth ratio varied from 1 to 3. The adaptability of HRB400 rebar, with critical yield strength of 400 MPa, used as stirrups was also verified. As the composite technology overcame the shortcomings of recycled coarse aggregate, CRAC had similar mechanical properties with those of conventional concrete. Details on the shear behaviors of test beams under a four-point loading test are presented. The results indicated that the changes of CRAC strain, stirrup strain, and shear-crack width depended on the failure patterns, which are controlled by the shear-span to depth ratio. The stirrups yield at the failure of reinforced CRAC beams. The shear cracking resistance and the shear capacity of reinforced CRAC beams can be predicted by the statistical equations. Based on the design codes GB50010, ACI318-19, Model Code 2010 and DIN-1045-1-2008 for conventional reinforced concrete beams, the shear strengths provided by CRAC and stirrups are statistical analyzed. The rationality of the design equations is examined by the utilization level of shear strength provided by CRAC. The maximum shear-crack widths are extracted from the test data of reinforced CRAC beams at normal service state. Comparatively, by specifying the lower limit of shear strength provided by the CRAC with various shear-span to depth ratios, China code GB50010 gives a rational method for utilizing CRAC. Under the premise that the design of shear capacity would give considerations to meet the normal serviceability, the factored strength of HRB400 rebar should be 360 MPa for the calculation of shear strength provided by stirrups. The design methods in codes of GB50010, ACI318-19 and Model Code 2010 are conservative for the shear capacity of reinforced CRAC beams.

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Section: Research Significancementioning

confidence: 99%

Shear Performance of Reinforced Concrete Beams Affected by Satisfactory Composite-Recycled Aggregates

Liang

Zhao

et al. 2020

Materials

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“…It is noteworthy that two thorough review studies by Silva et al [40] and Tošic et al [41] have clearly shown that the design code Eurocode 2 can provide a good prediction for the load-carrying capacity of RRC beams without stirrups. However, for the beams with stirrups, which are more significant in practice-the predictions by Eurocode 2 showed a remarkable gap compared to the measurements, suggesting that the underlying mechanisms still needed to be revealed towards more reliable designs.…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of Reinforced Recycled Aggregate Concrete Columns under Cyclic Loadings

et al. 2019

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Recycled concrete aggregates (RCAs) generated from construction and demolition activities have been recognized as a feasible alternative to natural aggregates (NAs). Naturally, the columns fabricated with reinforced recycled concrete (RRC) have been proposed and investigated to promote the structural use of recycled aggregate concrete (RAC). There is still, however, very limited modeling research available to reproduce, accurately and efficiently, the seismic response of RRC columns under lateral cyclic loading; proper evaluations are also lacking on addressing the columns’ seismic behaviors. To fill some of those research gaps, a fiber-based numerical model is developed in this study and then validated with the experimental results published in the literature. Subsequently, the numerical model justified is applied to carry out a comprehensive parametric study to examine the effects of a range of variables on the hysteretic characteristics of RRC columns. Furthermore, a grey relational analysis is conducted to establish quantifiable evidence of key variable sensitivities. The evaluation results imply that the use of the additional water method (AWM) for manufacturing RAC is likely to reduce the lateral load-carrying capacity of the RRC columns (up to 10%), whereas the opposite would occur if a conventional mixing procedure is adopted. Moreover, compared with other factors such as steel area ratio, the content of RCA replacement has a less remarkable effect on the seismic performance of the RRC columns. In general, the RRC columns possess acceptable seismic-resistant properties, and they can be used in earthquake-prone regions with confidence.

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“…Hence, in such cases (with shear reinforcement), the detrimental effects are not as prominent as in beams without shear reinforcement. Tošić et al [ 39 ] added their own test data to a comprehensive database for RAC beams, and evaluated the beams’ flexural and shear strengths using European design code. In the shear loading case, the code can successfully predict the ultimate force of RAC beams without stirrups, but it fails for the beams with stirrups.…”

Section: Introductionmentioning

confidence: 99%

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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A database on flexural and shear strength of reinforced recycled aggregate concrete beams and comparison to Eurocode 2 predictions

Cited by 56 publications

References 35 publications

Shear Performance of Reinforced Concrete Beams Affected by Satisfactory Composite-Recycled Aggregates

Shear Performance of Reinforced Concrete Beams Affected by Satisfactory Composite-Recycled Aggregates

Performance Evaluation of Reinforced Recycled Aggregate Concrete Columns under Cyclic Loadings

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

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