Influence of Recycled Aggregate Defects on the Durability of Recycled Aggregate Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 173-182 ◽  
Author(s):  
Gai Fei Peng ◽  
Juan Yang ◽  
Jing Yan Wang
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Water Penetration ◽  
Aggregate Concrete ◽  
Chloride Ion Penetration

An experimental investigation was conducted on the durability of recycled aggregate concretes with the water to binder ratios of 0.26 and 0.60, including chloride ion penetration resistance test, freezing-thawing resistance test and water penetration resistance. Natural aggregate, recycled aggregate untreated and recycled aggregate treated by sulfuric acid solution, were employed. Results indicated that, 3 mol/L acid concentration and the 7 days soaking duration was the optimum to remove the attached mortars in recycled aggregate, and its removal rate could reach to 90.8%. Water penetration resistance, chloride ion penetration resistance and freezing-thawing resistance of concrete with 0.26 W/B was superior to that of concrete with 0.60 W/B. The more pores in the internal of concrete with 0.60 W/B could be attributed to that. Durability of recycled aggregate concrete, incorporating recycled aggregate treated by sulfuric acid solution, was improved. In particular, the improvement in recycled high strength concrete was significant.

scholarly journals Prediction of Chloride Ion Penetration of Recycled Aggregate Concrete

2015 ◽  
Vol 18 (2) ◽  
pp. 427-440 ◽  
Author(s):  
Rui Vasco Silva ◽  
Jorge de Brito ◽  
Rui Neves ◽  
Ravindra Dhir
Keyword(s):  
Chloride Ion ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Chloride Ion Penetration ◽  
Ion Penetration

scholarly journals Application of X-Ray Computed Tomography in Monitoring Chloride Ion Penetration Paths in Recycled Aggregate Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Yuan Zuo ◽  
Bing Qi ◽  
Jianming Gao ◽  
Weibin Li
Keyword(s):  
Computed Tomography ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
X Ray ◽  
Chloride Ion Penetration ◽  
X Ray Computed ◽  
Ion Penetration

The penetration paths of chloride ions in recycled aggregate concrete (RAC) are of significant interest and have not been well studied previously. This study used X-ray computed tomography (X-CT) as a novel approach to investigate chloride ion penetration paths in RAC. The results indicate that X-CT can be used for the constant monitoring of chloride ion penetration paths in RAC, and the influence of mix proportions on the chloride ion penetration can be understood through the X-CT visualization.

Influence of Recycled Aggregate on Physical and Mechanical Properties of High Performance Recycled Aggregate Concrete

2011 ◽  
Vol 460-461 ◽  
pp. 764-767 ◽  
Author(s):  
Yi Dong Xu ◽  
Jia Ying Sun
Keyword(s):  
High Performance ◽  
Physical And Mechanical Properties ◽  
Chloride Ion ◽  
Poor Quality ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Ion Permeability ◽  
Negative Effects ◽  
Aggregate Concrete ◽  
Positive Effects

Influence of recycled aggregate on slump, compressive strength and chloride ion permeability of recycled aggregate concrete was investigated. As is shown by the results, although recycled aggregate belongs to the category of poor quality aggregate, the properties of high performance recycled aggregate concrete are not reduced dramatically with the increasing amount of recycled aggregate, for recycled aggregate have both positive effects and negative effects on the properties of recycled aggregate concrete. The high performance recycled aggregate concrete can be developed by double-mixture of ultra fine fly ash and superplasticizer.

An Experimental Study on the Chloride Penetration Resistance of Recycled Aggregate Concrete

2011 ◽  
Vol 71-78 ◽  
pp. 1255-1258
Author(s):  
Jian Jiang Ding ◽  
Jian Jun Zheng ◽  
Ting Lei ◽  
De Yu Kong
Keyword(s):  
Significant Influence ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Mixing Method ◽  
Chloride Penetration Resistance ◽  
Theoretical Evidence

The degradation of reinforced concrete structures due to chloride penetration has a significant influence on structural durability. In this study, an experiment is conducted to investigate the effects of the aggregate type, mixing method, and admixture type on the chloride penetration resistance of concrete. Based on the experimental results, it is found that, since more pores and microcracks are included in recycled aggregates, the chloride penetration resistance of recycled aggregate concrete is larger than that of natural aggregate concrete. Slag is more efficient than fly ash in increasing the chloride penetration resistance of recycled aggregate concrete. It is also found that the mixing method has a significant influence on the chloride penetration resistance of recycled aggregate concrete. These conclusions can provide theoretical evidence for the design optimization of recycled aggregate concrete properties.

scholarly journals Call for papers on special issue “Performance-based Service Life Design of reinforced recycled aggregate concrete”

2020 ◽  
Vol 2 (1) ◽  
pp. 045-045
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Chloride Ion ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Special Issue ◽  
Aggregate Concrete ◽  
Service Life Design ◽  
Life Design

Aim & Scope: Sustainability requires a judicious use of natural resources. Reducing the consumption of natural aggregates and ensuring adequate durability of reinforced concrete infrastructures are major steps towards sustainability. Performance-based Service Life Design and recycled aggregate concrete are intense research fields. Considering the research maturity of each subject on its own, it is time to couple them and deliver knowledge on performance-based Service Life Design for reinforced concrete structures incorporating recycled aggregates. This Special Issue of Materials International constitutes a way to disseminate results and findings from original studies, experimental programs, empirical, analytical and numerical modelling of initiation period (carbonation- and chloride ion-related), propagation period or both (service life). Probabilistic, semi-probabilistic and deterministic approaches are welcome.

Mechanical behaviors of GFRP tube confined recycled aggregate concrete with sea sand

2020 ◽  
pp. 136943322097477
Author(s):  
Yijie Huang ◽  
Jianzhuang Xiao ◽  
Li Qin ◽  
Peng Li
Keyword(s):  
Concrete Strength ◽  
Chloride Ion ◽  
Deformation Curve ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Experimental Program ◽  
Mechanical Behaviors ◽  
River Sand ◽  
Aggregate Concrete ◽  
Sea Sand

An experimental program was undertaken to study the mechanical behaviors of glass fiber-reinforced polymer (GFRP) tube confined recycled aggregate concrete with sea sand (GRACSS) under the axial compression. Two different parameters were mainly considered: recycled coarse aggregates (RCA) replacement percentage (0, 100%) and type of sand (sea sand, river sand). Typical influences of RCA and sea sand on the strength, the deformation and the load–deformation curve of GRACSS were investigated. The test results showed that the failure pattern of GRACSS was similar to that of GFRP tube confined ordinary concrete (GCOC). The strength of GRACSS decreased with an increasing RCA replacement percentage, while sea sand could reduce the negative effect of RCA. It is also found that the peak deformation of GRACSS increased with the increasing RCA replacement percentage whereas with decreasing sea sand chloride ion (Cl–) content. The stiffness of the specimen was obviously influenced by the concrete type. Research findings indicated that the axial load-deformation curve of GRACSS can be divided into elastic-plastic and hardening stages. An analytical expression was proposed to calculate the load-deformation curve of GRACSS. Finally, the finite element method (FEM) was applied to study the effects of outer tube thickness, concrete strength, RCA replacement percentage and Cl– content in sea sand on the mechanical behaviors (strength and deformation) of GRACSS.

Study on Effect of Performance of Recycled Aggregate Concrete with Secondary Manufacturing Shell Mixing Approach

2014 ◽  
Vol 1020 ◽  
pp. 80-85
Author(s):  
Jing Bo Mu ◽  
Ya Qian Cui
Keyword(s):  
Weak Link ◽  
Chloride Ion ◽  
High Water ◽  
Economic Benefits ◽  
Recycled Aggregate Concrete ◽  
Environmental Benefits ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
The Sustainable Development ◽  
Secondary Manufacturing

The application of recycled aggregate concrete (RAC) has environmental benefits, social benefits and economic benefits, which has profound significance to the sustainable development of society. However, recycled aggregate (RA) has a large porosity, high water absorption, high crush index, etc. In addition, the interface transition zone (ITZ) is the weak link of RAC, which has limited the application of RAC. Based on the advance of RAC, by discussing the characteristic of the ITZ of RAC, this paper proposes a secondary manufacturing shell mixing approach (SMSMA), and the mechanism of this mixing approach and its effect on performance of RAC are analyzed. Compared with the test of normal mixing approach (NMA), it indicates that compressive strength and splitting tensile strength of RAC through SMSMA are generally increased by about 10% ~ 25% and 10% ~ 40% at 28 days respectively, and the chloride ion diffusion coefficient are generally declined by about 10% ~ 15% at 28 days, but the liquidity of RAC is not improved. What's more, with replacement rate of RA dropping, the improvement of the performance of RAC tends to be better.

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