Composite Model for Time-Relative Compressive Strength of Recycled Coarse Aggregate Concrete

2013 ◽  
Vol 307 ◽  
pp. 395-398
Author(s):  
Bai Liang Yang ◽  
Wei Wang ◽  
Xu Chao Chi ◽  
Wen Hui Bai
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Hyperbolic Model ◽  
Strength Development ◽  
Engineering Structures ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Important Research Topic ◽  
Compressive Strength Development ◽  
Special Case

The compressive strength development process of recycled coarse aggregate concrete (RCAC) directly affects the safety of the engineering structures, which is an important research topic in the concrete mechanics. According to the statistics of the experimental results, the development mechanism principle of the compressive strength of RCAC gradually increasing with curing time was analyzed. The mathematical property was introduced to reveal the defects of the traditional hyperbolic model of the time-relative compressive strength (TRCS), and to point out that the mathematical nature of the ideal TRCS model should have. A new CES model was presented for TRCS. The mathematical analysis shows that the hyperbolic model is a special case of the CES model, and in another hand the CES model overcomes the defects of the hyperbolic model.

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.

EXPERIMENTAL INVESTIGATION ON SELF CURING RECYCLED AGGREGATE CONCRETE MEMBERS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
V. Bhikshma ◽  
J. Ravi Kumar
Keyword(s):  
Coarse Aggregate ◽  
Heat Of Hydration ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Strength Development ◽  
Curing Agent ◽  
Rc Beams ◽  
Aggregate Concrete ◽  
Peg 6000 ◽  
Recycled Coarse Aggregate

Self-curing concrete is an important aspect in strength development, which is neglected due to various reasons such as shortage of water, inaccessibility of structures during curing. Self-curing agents play important role in heat of hydration and strength development. The present study involves the use of self-curing agent polyethylene glycol (PEG 6000). In this investigation, M20 to M50 grade concrete has been considered to evaluate strength characteristics and flexural behavior using natural and recycled aggregate concrete. The various percentages of PEG 6000 have been used. The test result indicates self-curing concrete has indicated strength enhancement compared to conventional curing concrete. The strength for normal coarse aggregate concrete with a self-curing agent (PEG 6000) at 2% with 10% GGBS is decreased when compared with recycled coarse aggregate concrete with 1% (PEG 6000) with addition 10% GGBS. Mechanical properties are 7% to 20% higher for self-curing concrete when compared to natural concrete. Similarly, the flexural strength of normal coarse aggregate concrete was found to be varying from 4% to 16% more than with recycled coarse aggregate concrete at 28 days. Ultimate deflection of RC beams is 10% greater than the NC beams and ultimate moments of RC beams were 1% to 3% less than the corresponding NC beams. The moment-curvature relationship and load-deflection characteristics of the NC beams and RC beams show a similar trend.

Compressive Strength of Artificial Sand Recycled Concrete with Different Content of Stone Powder

2014 ◽  
Vol 578-579 ◽  
pp. 464-468
Author(s):  
Wen Wu Lan ◽  
Rong Fu Zhong ◽  
Bo Lv ◽  
Jing Yan Gan ◽  
Jing Wei Ying
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Concrete Mixture ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregate ◽  
Different Content

This study examined the compressive behaviors of concrete with artificial sand that mixed with different content of stone powder (SP). Forty-five cubic specimens were prepared with two strength grades and five SP-content. Including 15 specimens (C35) of recycled coarse aggregate (RA) concrete with artificial sand (RCC35), 15 specimens (C45) of recycled coarse aggregate concrete with artificial sand (RCC45) and 15 specimens (C35) of natural aggregate concrete with artificial sand (NC35). The workability of concrete mixture and the compressive strength of the cubic specimens were tested. The results showed that the slump of concrete mixture decreased with the SP-content increased, and the coagulability and water retentivity of the concrete mixture were improved by using stone powder. The compressive strength of the concrete with artificial sand were increased by incorporating stone powder. The optimal SP-content of RCC35 and NC35 is 20%, while RCC45 is 10%.

Compressive Strength Estimation of Recycled Coarse Aggregate Concrete Using Ultrasonic Pulse Velocity

2011 ◽  
Vol 147 ◽  
pp. 288-292 ◽  
Author(s):  
Yong Taeg Lee ◽  
Seong Uk Hong ◽  
Hyun Suk Jang ◽  
Sang Ki Baek ◽  
Young Sang Cho
Keyword(s):  
Compressive Strength ◽  
Wave Velocity ◽  
Coarse Aggregate ◽  
Pulse Velocity ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Design Standard ◽  
Recycled Coarse Aggregate

National effort to recycle construction waste as structural concrete usage of high economic value is ongoing, but performance rate of recycling is a low-level due to a lack of awareness on the recycled aggregates. Accordingly, the goal of this study was to verify the structural applicability of recycled aggregates. This study compared a compressive strength based on the replacement ratio of natural aggregate and recycled aggregate, and analyzed a correlation of wave velocity due to the increase in compressive strength under the same condition. The 『design standard strength – replacement ratio of recycled coarse aggregate』 was set to total 12 combinations by applying 0, 30, 50, 100[%] replacement ratio of recycled coarse aggregate to 21, 27, 35[MPa] to the design standard strength. During the experiment of fracture strength, strength degradation due to the replacement rate of recycled coarse aggregate did not occur, and it was found that the wave velocity also increased along with an increase in strength due to the age of recycled coarse aggregate concrete.

Expermental Research on Compression Strength of Recycled

2012 ◽  
Vol 503-504 ◽  
pp. 1112-1115
Author(s):  
Fang Yu ◽  
Can Bin Yin ◽  
Min Jiang
Keyword(s):  
Compressive Strength ◽  
Experimental Work ◽  
Compression Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

Experimental work for the compressive strength of recycled aggregate concrete was designed. The results indicated that the recycled coarse aggregate (RCA) re-placement ratio has a remarkable influence on the compressive strength of recycled aggregate concrete.the relationships between the compressive strength and themw/mcratio are also different for differentRCA replacement ratios and the developments for the compressive strength of recycled aggregate concrete are not exactly the same as that of normal concrete.

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