Effects of Recycled Aggregates on Water-Cement Ratio for Concrete

2013 ◽  
Vol 423-426 ◽  
pp. 1010-1013 ◽  
Author(s):  
Wee Kang Choong ◽  
Lau Teck Leong ◽  
Choon Seng Sin ◽  
Abdullahi Ali Mohamed
Keyword(s):  
Cement Mortar ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Structural Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Different Origins ◽  
Concrete Elements

Recycled aggregate differs from primary aggregate in that it constitutes of two types of materials: the primary aggregate and the attaching cement mortar. This study was conducted in order to investigate the effects on water-cement ratio for concrete cast with recycled aggregates derived from different origins (hollow blocks & structural concrete elements) and different mixed proportions of recycled aggregate contents. The outcomes of test indicate that higher water cement ratios are required for concrete cast with recycled aggregates as compare to those cast with primary aggregates. Also there appear no obvious relationships or consistencies that can be drawn among types of recycled aggregate.

scholarly journals Experimental and Statistical Evaluation of the Interaction Effect of Recycled Aggregate and Water/Cement Ratio on Concrete Compressive Strength

2021 ◽  
Vol 03 (03) ◽  
pp. 1-1
Author(s):  
Mônica Batista Leite ◽  
◽  
Paulo Roberto Lopes Lima ◽  
Keyword(s):  
Compressive Strength ◽  
Interaction Model ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Aggregate Content ◽  
Factorial Design Experiment

The production of concrete using recycled aggregates, obtained from the processing of construction and demolition waste, is extensively practiced worldwide. However, the effect of simultaneous adding fine recycled aggregate and the recycled coarse aggregate on the mechanical properties of concrete is still unfamiliar. This work aims to evaluate the influence of the water/cement ratio (WC Ratio), the fine recycled aggregate content (%FRA), the coarse recycled aggregate content (%CRA), as well as the interaction between factors on the compressive strength of concrete. Accordingly, a factorial design experiment was developed, analyzing these factors at three levels, which resulted in the production of 27 mixtures. These levels were: WC Ratio (0.50; 0.65 and 0.80); %FRA (0; 50 and 100) and %CRA (0; 50 and 100). Statistical analysis was performed on the response surface, and an enhanced approximation of the two-way interaction model was identified. The results indicate that the substitution of the natural aggregate with recycled aggregate shows a significant influence on the compressive strength, and its effect depends on the water-cement ratio. Furthermore, considering the interaction between the content and type of aggregate and the water-cement ratio is fundamental for obtaining the proper mix design of this type of concrete.

Study on Preparation of Solid Concrete Brick with Recycled Aggregate

2013 ◽  
Vol 648 ◽  
pp. 108-111
Author(s):  
Qi Jin Li ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Mass Fraction ◽  
Recycled Aggregate ◽  
Preparation Process ◽  
Mass Ratio ◽  
Construction Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Optimal Value

The construction waste was processed into recycled aggregate to produce solid construction waste brick with grade of MU20. The preparation process of recycled aggregate and the optimal value of mass ratio of water to cement (water cement ratio) and mass ratio of recycled aggregate to cement was studied. The results shows that when the water cement ratio is 0.86 and the mass ratio of recycled aggregate to cement is 5.5 and the dosage of activator is 0.25% (mass fraction with recycled aggregate), the compressive strength of sample is 22.5MPa and can be satisfied with the requirement of MU20 solid concrete brick.

Extended water/cement ratio law for cement mortar containing recycled asphalt pavement

2019 ◽  
Vol 196 ◽  
pp. 457-467 ◽  
Author(s):  
Komkorn Chaidachatorn ◽  
Jirayut Suebsuk ◽  
Suksun Horpibulsuk ◽  
Arul Arulrajah
Keyword(s):  
Cement Mortar ◽  
Asphalt Pavement ◽  
Recycled Asphalt Pavement ◽  
Recycled Asphalt ◽  
Cement Ratio ◽  
Water Cement Ratio

Structural Concrete with Recycled Aggregate: Advances in Mechanical Properties, Durability and Sustainability

2016 ◽  
Vol 847 ◽  
pp. 553-558 ◽  
Author(s):  
Marc Antonio Liotta ◽  
Marco Viviani ◽  
Carlotta Rodriquez
Keyword(s):  
Cement Mortar ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mix Design ◽  
Elastic Behavior ◽  
Structural Concrete ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Ordinary Concrete

A large number of tests has been carried out in the last 15 years all around the world to study the possibility to use recycled concrete aggregates (RCA) to produce structural concrete.Earlier tests indicated that RCA concrete had lower properties in comparison to ordinary concrete, such as lower elastic modulus, a more brittle post-elastic behavior, lower workability, higher shrinkage and creep.Most of these issues have been addressed to the content of cement mortar remaining in adhesion to the aggregate after the recycling processes and that cannot be totally eliminated without high economic and ecological costs. This cement mortar which has undergone the crushing process creates zones of weakness in the RCA, causes higher water absorption, higher concrete porosity and causes the decay of the aforementioned properties.More recent tests prove that Recycled Concrete shows this peculiar problems only with a percentage of substitution of standard aggregates with RCA higher than 30%. Under this percentage recycled aggregate concrete (RAC) can be considered as a standard concrete, on condition that an appropriate mix design is performed.

THE EFFECT OF ADDITION NANOPARTICLES ON SHRINKAGE PROPERTY OF ORDINARY PORTLAND CEMENT

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-78-2-82
Author(s):  
Haider K. Ahmed ◽  
◽  
Mohammed A. Abdulrehman ◽  
Keyword(s):  
Compressive Strength ◽  
Carbon Black ◽  
Portland Cement ◽  
Cement Mortar ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Carbon Black Nanoparticles ◽  
Flow Table ◽  
Compressive Strength Test ◽  
Negative Effect

Two types of nanomaterial: Tio2 nanoparticles (NPs) and carbon black NPs have used in this research to study their effect on compressive strength, shrinkage and flow table tests Cement mortar. The mixing ratio was 1:2.7:0.485 (cement, sand, water/cement ratio) for compressive strength test and 1:2 (cement, sand) with the water/cement ratio was a variable value for dry shrinkage test. The two nanoparticles’ ratios are (0.25%, 0.75%, 1.25 % and 1.75%) by weight of the Portland cement. The test results show that the highest value of compressive strength was obtained when using Tio2 at 1.25% wt. of cement. But when using carbon black nanoparticles, the greatest value was obtained when adding it with a ratio of 1.75 % wt. of cement. Using two NPs when added to cement mortar has a negative effect on the shrinkage value.

Effect of Admixed Recycled Aggregate on Properties of Recycled Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 743-746
Author(s):  
Ya Jun Zhao ◽  
Ying Gao ◽  
Li Li He
Keyword(s):  
Compressive Strength ◽  
Design Method ◽  
Orthogonal Design ◽  
Plain Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Influence Of Water ◽  
The Impact

The mixture proportion of recycled concrete was discussed by orthogonal design method. The influence of water-cement ratio, recycled aggregate quantity on workability, cube compressive strength of recycled concrete was analyzed. The experimental results indicated that，Recycled concrete mix proportion design should consider the impact of the water absorption of recycled aggregate. Unit water amount of recycled concrete should be plain concrete unit water consumption and recycled aggregate additional amount of water. Sand ratio should increase in the corresponding ordinary aggregate concrete sand ratio on the basis of 1 to 3 percent. When the water-cement ratio is 0.36 and construction waste content of 40% slag content of 20%, 28d compressive strength of concrete is 48.1MPa, slightly higher than the reference concrete (48.0MPa).

Effect of Molasses and Water–Cement Ratio on Properties of Recycled Aggregate Concrete

2019 ◽  
Vol 45 (5) ◽  
pp. 3455-3467 ◽  
Author(s):  
Babar Ali ◽  
Liaqat Ali Qureshi ◽  
Hassan Sardar Baig ◽  
Shahbaz Malik ◽  
Muhammad Din ◽  
...  
Keyword(s):  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio
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