Flexural behavior of reinforced geopolymer concrete beams with recycled coarse aggregates

2021 ◽  
pp. 136943322110262
Author(s):  
Haiyan Zhang ◽  
Keyue Wan ◽  
Bo Wu ◽  
Zhonghao Hu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Flexural Behavior ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Bending Capacity

Geopolymer recycled aggregate concrete (GRAC) is a new green construction material, which uses geopolymer as the binder and recycled concrete as aggregates. To compare the flexural performance of GRAC and ordinary recycled aggregate concrete (RAC) beams, static loading tests were conducted on seven GRAC beams and three RAC beams. The effects of the replacement ratio of recycled aggregates (RAs), the replacement patterns, and the reinforcement ratio on the flexural behavior of GRAC beams are evaluated. The test data show that the replacement ratio has no significant effect on the cracking pattern, failure mode, or bending capacity of GRAC beams, but the replacement pattern does have an effect. Under a given replacement ratio, replacing only the larger fraction of natural aggregates (NA) with RA improves the concrete strength and crack resistance of both RAC and GRAC beams, compared to that using same replacement percentage for all fractions. Due to the lower elastic modulus and strength of GRAC prepared in this study, the GRAC beams have lower height of neutral axis and greater deflection than RAC beams at the same load level and possess slightly lower cracking load, bending capacity, and ductility. The bending capacity of GRAC beams can be predicted by the formulas proposed for ordinary reinforced concrete beams in the Chinese code GB50010-2010, ACI 318-11, or BS EN 1992-1-1:2004 codes, but the safety margin is generally lower than that of ordinary reinforced concrete beams.

scholarly journals Verification of a Torsional Behaviour Prediction Model for Reinforced Recycled Aggregate Concrete Beams

2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Aqeel H. Chkheiwer ◽  
Mazin A. Ahmed ◽  
Zahir M. N. Hassan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Cross Sectional ◽  
Recycled Concrete Aggregates ◽  
Concrete Recycling

This study shows the torsional conduct of aggregate streaming beams of reinforced concrete recycling. Pure torsion was perceived for 15 reinforced concrete beams containing recycled concrete aggregates. The beams were grouped into five lengths and cross-sectional groups. The study’s principal parameters were the various percentages of longitudinal steel reinforcement and the proportions of recycled aggregates. The beams were purely twisted until failure and investigated for torsional and crack behaviour. The findings show that the beams with maximum steel enhancement and standard aggregate exhibited maximum cracking power and ultimate torsional strength. Recycled aggregates increased the presence of splitting and the ultimate strength, and the effects of steel strengthening in recycled beams were apparent. In a second analysis, the whole torsional reaction of the beams was analytically predicted. A soft truss model was used and matched with test results for standard beams. A strong compromise was generally reached.

Experimental Study on Compressive Strength of Recycled Aggregate Concrete with Different Replacement Ratios

2012 ◽  
Vol 174-177 ◽  
pp. 1277-1280 ◽  
Author(s):  
Hai Yong Cai ◽  
Min Zhang ◽  
Ling Bo Dang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Failure Mode ◽  
Failure Process ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Replacement Ratio ◽  
Aggregate Concrete

Compressive strengths of recycled aggregate concrete(RAC) with different recycled aggregates(RA) replacement ratios at 7d, 28d, 60d ages are investigated respectively. Failure process and failure mode of RAC are analyzed, influences on compressive strength with same mix ratio and different RA replacement ratios are analyzed, and the reason is investigated in this paper. The experimental results indicate that compressive strength of recycled concrete at 28d age can reach the standard generally, it is feasible to mix concrete with recycled aggregates, compressive strength with 50% replacement ratio is relatively high.

Compressive Behaviour of Recycle Concrete Cubes after Freeze-Thaw Cycles

2013 ◽  
Vol 671-674 ◽  
pp. 1865-1868
Author(s):  
Tao Long ◽  
Shi Hai Dong ◽  
Shi Ming Cui ◽  
Qing Yuan Wang
Keyword(s):  
Carrying Capacity ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Recycle Concrete ◽  
Ultimate Carrying Capacity

It is widely considered that crushed construction aggregate waste creates a lower compressive strength kind of concrete. This paper presents experimental investigation on axial compression strength of 18 recycled aggregate concrete cubes under the freeze-thaw test. The research has focused on the effect of the freezing-thawing test on the ultimate carrying capacity of recycled concrete cubes with different coarse aggregate replacement ratio. This study confirms that freezing-thawing cycles have a greater effect on the ultimate bearing capacity of recycled concrete cubes. Some measures should be taken to prevent the recycle concrete from the freeze-thaw damage, for example add air entraining agent to concrete.

Experimental Study on Flexural Property of Reinforced Concrete Beams with Recycled Aggregate of Construction Waste

2012 ◽  
Vol 517 ◽  
pp. 601-605
Author(s):  
Zhao Hua Du ◽  
Tong Hao ◽  
Li Xin Liu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Flexural Property ◽  
Test Results ◽  
Replacement Rate ◽  
Construction Waste

This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of and with different recycled aggregate replacement rate. The results indicate: the ultimate bearing capacity of recycled concrete beams with natural aggregate concrete beams are almost the same, and can meet the requirements of chinese code; The cracking resistance of the reinforced recycled concrete beams is slightly less than that of the beams with natural aggregates, the influence of recycled aggregate replacement rate to cracking resistance is not obvious. Recycled concrete beam crack load the calculated value is greater than the measured value, should carry out the theoretical value adjustment. Reinforced concrete beams is one of concrete structures, its the most common and most important component, Study of flexural property of reinforced concrete for recycled concrete structure component in the popularization and application to have the important significance [. This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of C30 and C40 and with different recycled aggregate replacement rate of 0%, 50% and 70%. These results may be as a reference for the application of the concrete with recycled aggregates of construction waste in engineering [2,3,.

scholarly journals Analytical Model to Predict Residual Flexural Capacity of Recycled Aggregate Concrete Beams with Corroded Longitudinal Rebars

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhenghao Zou ◽  
Guojiao Yang ◽  
Tian Su
Keyword(s):  
Experimental Data ◽  
Theoretical Analysis ◽  
Strain Distribution ◽  
Concrete Beams ◽  
Plane Section ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Aggregate Concrete

This paper presents the results of research on the flexural behavior of recycled aggregate concrete (RAC) beams. The correlation between flexural behavior and the corrosion level of longitudinal rebar was analysed. Based on theoretical analysis and experiment results, the influence of corrosion on flexural cracking moment was analysed and a model to predict the residual flexural capacity of RAC beams with corroded longitudinal rebars was established. The experimental results show that the development degree of cover cracks deepens with the increase of the corrosion level, and the experimental data also demonstrate that the strain distribution of concrete in the midspan of beams conforms to the plane section assumption better when the corrosion level is little but no longer satisfies the plane section assumption when the corrosion level is high.

Shear-Crack Behaviors of Reinforced Full-Recycled Aggregate Concrete Beams

2013 ◽  
Vol 438-439 ◽  
pp. 794-799 ◽  
Author(s):  
Chang Yong Li ◽  
Guang Xin Li ◽  
Wen Jing Shao ◽  
Qi Guo ◽  
Rui Liu
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Shear Crack ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Shear Span ◽  
Shear Cracking

On the basis of experimental results, this paper discusses the shear-crack behaviors such as shear-cracking force and shear-crack width of reinforced full-recycled aggregate concrete beams. The full-recycled aggregate concrete was developed for the sustainable development in civil engineering, in which the coarse aggregate was the recycled aggregate made of abandoned concrete, and the fine aggregate was the machine-made sand. Sixteen beams, six of them without stirrups, were tested with the shear-span ratio varying as 1.5, 2.0 and 3.0, and the ratio of stirrups varying from 0.19% to 0.35%. The results showed that the shear-cracking force of the beam was mainly affected by the shear-span ratio, the width of shear-cracks intersecting stirrups decreased with the increasing ratio of stirrups, but the maximum crack width almost exceeded the limit 0.3mm in the first class environmental condition specified in Chinese code GB50010-2010. Comparing the calculation results by substituting the test parameters of full-recycled aggregate concrete beams into the formula of ordinary reinforced concrete beams, the lower resistance of reinforced recycled concrete beam to shear-cracking, and the larger crack width intersecting stirrups should be noted in the structural design. Based on the test data, the formula for calculating the shear-cracking force and the shear-crack width of reinforced full-recycled aggregate concrete beams are suggested.

Fractal Study for Surface Cracks on the Recycled Concrete Beams with Recycled Bricks

2012 ◽  
Vol 251 ◽  
pp. 426-430
Author(s):  
Hong Quan Sun ◽  
Jian Guo
Keyword(s):  
Fractal Dimension ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Surface Cracks ◽  
Concentrated Load ◽  
Aggregate Concrete ◽  
Damage Degree

In this paper, the experimental research on crack of four recycled aggregate concrete simple beams under a concentrated load was presented. Through the analysis of evolution and distribution characteristics of cracks with different amount of recycled brick, it is verified that the surface cracks on the recycled aggregate concrete beams have a very good fractal behavior. The research shows that the content of the recycled brick has obvious influence on the fractal dimension of the surface cracks of the beams. The more the content of the recycled brick is, the bigger the fractal dimension is. So the fractal dimension can be regarded as an index to evaluate damage degree of the recycled aggregate concrete beam. This research provides a novel idea and a method for studying the damage of the concrete structures.

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