scholarly journals Expansion and strength properties of concrete containing contaminated recycled concrete aggregate

2018 ◽  
Vol 9 ◽  
pp. e00201 ◽  
Author(s):  
Sallal R. Abid ◽  
Ali H. Nahhab ◽  
Husam K.H. Al-aayedi ◽  
Athraa M. Nuhair
Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 430
Author(s):  
Jawad Ahmad ◽  
Rebeca Martínez-García ◽  
Jesús de-Prado-Gil ◽  
Kashif Irshad ◽  
Mohammed A. El-Shorbagy ◽  
...  

The current practice of concrete is thought to be unsuitable because it consumes large amounts of cement, sand, and aggregate, which causes depletion of natural resources. In this study, a step towards sustainable concrete was made by utilizing recycled concrete aggregate (RCA) as a coarse aggregate. However, researchers show that RCA causes a decrease in the performance of concrete due to porous nature. In this study, waste glass (WG) was used as a filler material that filled the voids between RCA to offset its negative impact on concrete performance. The substitution ratio of WG was 10, 20, or 30% by weight of cement, and RCA was 20, 40, and 60% by weight of coarse aggregate. The slump cone test was used to assess the fresh property, while compressive, split tensile, and punching strength were used to assess the mechanical performance. Test results indicated that the workability of concrete decreased with substitution of WG and RCA while mechanical performance improved up to a certain limit and then decreased due to lack of workability. Furthermore, a statical tool response surface methodology was used to predict various strength properties and optimization of RCA and WG.


2019 ◽  
Vol 7 (SI-TeMIC18) ◽  
Author(s):  
Mohd Afiq Mohd Fauzi Mohd Fauzi ◽  
Ahmad Ruslan Mohd Ridzuan ◽  
Mohd Fadzil Arshad ◽  
Nurliza Jasmi ◽  
Mohd Shafee Harun ◽  
...  

Self-Consolidating Concrete (SCC) is developing class of concrete materials that offers great potential to improved ease of positioning and cost through reduced time and labor. Generally, amount of Construction and Demolition Wastes (C&DW) are increased daily. Therefore, it is beneficial to final usage of coarse recycled concrete aggregate that produced from crushed concrete waste as a new construction solution. Researchers have found that waste materials have unique properties that could help in improving the quality of self-consolidating concrete produced. Therefore, reuse of RCA generated as the supplemental material for the replacement of aggregate are significant in reducing the environmental impact. This research was focused on the strength characteristic and the chloride permeability level of SCC containing RCA. The influence of RCA content in the range from 0% to 100% of Natural Aggregate (NA) to the strength characteristic and the chloride permeability level of SCC was identified and compared with SCC containing normal mixes. In this research, three (3) series of concrete specimens were cast with different water cement ratios (0.53, 0.49 and 0.45). The concrete specimens were subjected to strength at the age of 3, 7, 14, 21, 28, 56 and 90 days and durability at the age of 28, 56 and 90 days. The result shown that the compressive strength and chloride permeability of SCC containing 100% RCA replacement give better performance than the 0% RCA replacement. Based on the finding, SCC containing 100% RCA replacement can be categorized similar to conventional concrete hence it can be utilized for construction purposes. RCA can also acts as an alternative replacement in concrete for replacing the NA. Keywords: Strength Properties; Rapid Chloride Permeability Test; Self Consolidating Concrete; Recycled Concrete Aggregate


2021 ◽  
Vol 13 (8) ◽  
pp. 4245
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas

The construction sector is currently struggling with the reuse of waste originating from the demolition and modernization of buildings and roads. Furthermore, old buildings are gradually being replaced by new structures. This brings a significant increase of concrete debris to waste landfills. To prevent this, many studies on the possibilities of recycling concrete, known as recycled concrete aggregate (RCA), have been done. To broaden the applicability of reused concrete, an understanding of its properties and engineering behavior is required. A difficulty in sustainable, proper management of RCA is the shortage of appropriate test results necessary to assess its utility. For this reason, in the present study, the physical, deformation, and stiffness properties of RCA with gravely grain distribution were analyzed carefully in the geotechnical laboratory. To examine the mentioned properties, an extensive experimental program was planned, which included the following studies: granulometric analysis, Proctor and oedometer tests, as well as resonant column tests. The obtained research results show that RCA has lower values of deformation and stiffness parameters than natural aggregates. However, after applying in oedometer apparatus repetitive cycles of loading/unloading/reloading, some significant improvement in the values of the parameters studied was noticed, most likely due to susceptibility to static compaction. Moreover, some critical reduction in the range of linear response of RCA to dynamic loading was observed.


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