scholarly journals Effect of River Indus Sand and Recycled Concrete Aggregates as Fine and Coarse Replacement on Properties of Concrete

2019 ◽  
Vol 9 (1) ◽  
pp. 3832-3835 ◽  
Author(s):  
A. R. Sandhu ◽  
M. T. Lakhiar ◽  
A. A. Jhatial ◽  
H. Karira ◽  
Q. B. Jamali
Keyword(s):  
Tensile Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Compressive Strength Of Concrete ◽  
River Indus ◽  
Concrete Materials

As the demand for concrete rises, the concrete materials demand increases. Aggregates occupy 75% of concrete. A vast amount of aggregates is utilized in concrete while aggregate natural resources are reducing. To overcome this problem, River Indus sand (RIS) and recycled concrete aggregate (RCA) were utilized as fine and coarse aggregate respectively. The aim of this experimental investigation is to evaluate the workability, and compressive and tensile strength of concrete utilizing RIS and RCA. Concrete samples of 1:2:4 proportions were cast, water cured for 7, 14, 21 and 28 days, and tested for compressive and tensile strength. The outcomes demonstrate that concrete possessed less workability when RIS and RCA were utilized. It was predicted that compressive strength of concrete would reduce up to 1.5% when 50% RIS and 50% RCA were utilized in concrete and 11.5% when natural aggregate was fully replaced by RIS and RCA, whereas the tensile strength decreased up to 1.60% when 50% by 12% respectively.

Modified recycled concrete aggregates for asphalt mixture using microbial calcite precipitation

RSC Advances ◽  
2015 ◽  
Vol 5 (44) ◽  
pp. 34854-34863 ◽  
Author(s):  
Zhong-Yao Pan ◽  
Gengying Li ◽  
Cheng-Yu Hong ◽  
Hui-Ling Kuang ◽  
Yu Yu ◽  
...  
Keyword(s):  
Bonding Strength ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Calcite Precipitation ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Porosity And Permeability

Recycled concrete aggregate (RCA) was pretreated by microbial calcite precipitation. The surface treatment reduced the porosity and permeability of RCA by 32% and 86.5%, respectively. The treatment improved the bonding strength of RCA–asphalt binder by 55%.

Experimental Study on Fundamental Characteristic of Recycled Concrete

2010 ◽  
Vol 146-147 ◽  
pp. 1925-1929
Author(s):  
Yuan Xu ◽  
Ru Heng Wang ◽  
Hua Chuan Yao
Keyword(s):  
Fly Ash ◽  
Maximum Size ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Fundamental Characteristic ◽  
Recycled Concrete Aggregate ◽  
Application Process ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Natural Rock

First, the fundamental characteristic of recycled concrete aggregate wasstudied. Then, the recycled concrete spiciemen with different maximum size was tested. The results showed that: the apparent density and bulk density of recycled concrete aggregates was smaller than the natural rock, but the moisture content, crushed index, water absorption was higher. The workability of recycled concrete improved with increase of water and fly ash, but its strength decreased as the increase of water and fly ash. The research on performance and strength of recycled concrete aggregate will provide certain theoretical basis in the application process.

Potential water pollution from recycled concrete aggregate material

2021 ◽  
Vol 72 (1) ◽  
pp. 58
Author(s):  
K. Purdy ◽  
J. K. Reynolds ◽  
I. A. Wright
Keyword(s):  
Water Contamination ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Water Pipe ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Road Base ◽  
Final Treatment ◽  
Aggregate Material

Recycled concrete aggregates (RCA) are a widely used recycled building material. RCA materials have many uses such as a road base or backfilling trenches. Our study investigated the potential water-contamination risks of water exposed to RCA materials. We recirculated water for 60min through four different treatments. Two treatments were a PVC gutter filled with different size grades of RCA material (20mm and 45mm), the third treatment was a clean PVC gutter and the fourth and final treatment was an unused concrete water pipe. Results showed that RCA material exposed to water released a suite of contaminants that could be ecologically hazardous to aquatic species. RCA leached metals over the 60-min recirculation (aluminium, arsenic, barium, chromium, lead, manganese, molybdenum, titanium, lithium and strontium). Water exposed to RCA material exceeded aquatic ecosystem guidelines for aluminium by 50 times and lead by up to 12 times. RCA materials increased pH by up to 4.35 pH units and electrical conductivity (EC) by up to 11 times the starting EC (mean 27.9 µs cm–1). We suggest that RCA materials need to be used with caution in settings that could be exposed to water and flow to waterways of conservation value.

SCC Produced with Recycled Concrete Aggregates

2012 ◽  
Vol 512-515 ◽  
pp. 2986-2989 ◽  
Author(s):  
Yuan Yong ◽  
Ueda Takao ◽  
Chun Long Yu
Keyword(s):  
Construction Industry ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Noise Emission ◽  
Self Compacting Concrete ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Complicated Process ◽  
Traditional Construction

The major content in concrete is aggregates. Reduce its usage and replaced with recycled concrete aggregate (RCA) could not only mitigate consuming of natural resources but avoid the treatment of solid wastes. Furthermore, producing self-compacting concrete (SCC) with RCA is a way for traditional construction industry in saving energy and avoiding noise emission. To seek the proper way in preparation of SCC with RCA, preparation of RCA, composition design, microstructure evolution with hydration, and mechanical properties are investigated within this study. It is found that successful producing of SCC with RCA is not a complicated process.

scholarly journals Performance Evaluation of Stone Mastic Asphalt and Hot Mix Asphalt Mixtures Containing Recycled Concrete Aggregate

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammad Saeed Pourtahmasb ◽  
Mohamed Rehan Karim
Keyword(s):  
Hot Mix Asphalt ◽  
Asphalt Mixtures ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Mastic Asphalt ◽  
Stone Mastic Asphalt ◽  
Economic Considerations

Environmental and economic considerations have encouraged civil engineers to find ways to reuse recycled materials in new constructions. The current paper presents an experimental research on the possibility of utilizing recycled concrete aggregates (RCA) in stone mastic asphalt (SMA) and hot mix asphalt (HMA) mixtures. Three categories of RCA in various percentages were mixed with virgin granite aggregates to produce SMA and HMA specimens. The obtained results indicated that, regardless of the RCA particular sizes, the use of RCA to replace virgin aggregates increased the needed binder content in the asphalt mixtures. Moreover, it was found that even though the volumetric and mechanical properties of the asphalt mixtures are highly affected by the sizes and percentages of the RCA but, based on the demands of the project and traffic volume, utilizing specific amounts of RCA in both types of mixtures could easily satisfy the standard requirements.

scholarly journals Mechanical Performance of Gilsonite Modified Asphalt Mixture Containing Recycled Concrete Aggregate

2021 ◽  
Vol 11 (10) ◽  
pp. 4409
Author(s):  
Daniel Alberto Zuluaga-Astudillo ◽  
Hugo Alexander Rondón-Quintana ◽  
Carlos Alfonso Zafra-Mejía
Keyword(s):  
Mechanical Performance ◽  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Coarse Fraction ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates

Hot-mix asphalts exposed to hot weather and high traffic volumes can display rutting distress. A material that can be used to increase the stiffness of asphalt binders is gilsonite. On the other hand, from an environmental point of view, the virgin natural aggregates of asphalt mixtures can be replaced with recycled concrete aggregates. For these reasons, this study modified the asphalt binder with gilsonite by wet-process to improve rutting resistance, and replaced (by mass and volume) part of the coarse fraction of the aggregate with recycled concrete aggregate in two hot-mix asphalts with different gradations. Unlike other studies, a larger experimental phase was used here. Marshall, indirect tensile strength, resilient modulus, permanent deformation, fatigue resistance, and Cantabro tests were performed. An ANOVA test was carried out. If the replacement of the virgin aggregate by recycled concrete aggregates was made by volume, both materials (gilsonite and recycled concrete aggregate) could be used in hot-mix asphalts for thick-asphalt layers in high temperature climates and any level of traffic. The use of both materials in hot-mix asphalts is not recommended for thin-asphalt layers in low temperatures climates. It is not advisable to replace the aggregates by mass.

scholarly journals Soil-Geopolymer Mixtures Using Recycled Concrete Aggregates for Base and Subbase Layers

2019 ◽  
Vol 271 ◽  
pp. 02003
Author(s):  
Daniel Odion ◽  
Mohammed J Khattak ◽  
Makarios Abader ◽  
Nathan Heim
Keyword(s):  
Road Construction ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Road Base ◽  
Soil Cement ◽  
Selection Of ◽  
Properties Of Soil

The recycling of concrete aggregates has become a viable venture to investigate particularly its application in road construction. This study was conducted to proffer the feasibility of using recycled concrete aggregate (RCA) mixed with soil, flyash and alkali activator as an alternative to soil-cement in road base or subbase applications. The resulting product known as Soil-RCA geopolymer was made by varied mix constituents of flyash, RCA, sodium silicate, and sodium hydroxide. The influence of mixture variables on the mechanical properties of Soil-RCA geopolymer was investigated through an experiment design using two different flyash. Models to predict the unconfined compressive strengths based on mixture parameters were also established for the sensitivity analysis and selection of final mixtures. The results and analysis showed that the Soil-RCA geopolymer mixture exhibited sound strength, stiffness and durability characteristics.

scholarly journals Review of Research on and Implementation of Recycled Concrete Aggregate in the GCC

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Akmal S. Abdelfatah ◽  
Sami W. Tabsh
Keyword(s):  
Recycled Concrete ◽  
Sustainable Construction ◽  
Practical Implementation ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Current Time ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Published Research ◽  
Main Material

The goal of sustainable construction is to reduce the environmental impact of a constructed facility over its lifetime. Concrete is the main material used in construction in the Gulf Cooperation Council (GCC). Therefore, it makes economic and environmental sense to use recycled materials in the making of new concrete for different applications. The objectives of this study are to summarize published research on the use of recycled concrete aggregates in new concrete mixes and examine its implementation in construction and industry in the GCC region. The study showed that while there is reasonable research on recycled concrete, the practical implementation in the region greatly lacks behind, especially due to the lack of economic viability and awareness of such applications at the current time.

scholarly journals Effect of Steel Fibers on the Performance of Concrete Made with Recycled Concrete Aggregates and Dune Sand

2020 ◽  
Vol 9 (1) ◽  
pp. 2188-2193
Keyword(s):  
Coarse Aggregate ◽  
Preliminary Test ◽  
Recycled Concrete ◽  
Steel Fibers ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Dune Sand ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Acid Test

This paper aims to develop and evaluate the performance of concrete made with recycled concrete aggregates (RCA) and dune sand (DS) in addition with steel fibers (SF). This work is mainly intended to find the effective ways to reutilize the recycled concrete aggregates as coarse aggregate and due to sand demand dune sand were used as a fine aggregate. Different mechanical and durability properties of recycled concrete aggregates (RCA) and dune sand (DS) concrete mixtures were evaluated. To ensure the properties of cement, fine aggregate, coarse aggregate, recycled concrete aggregate and dune sand preliminary test were determined. Mix design is formulated based on its properties and requirements. Experimentation has been done by using M25 grade concrete. Ordinary Portland cement is used. Fine aggregate and coarse aggregate were partially replaced by recycled concrete aggregates and dune sand at different proportions (25%, 50%, 75%) in addition with 0.25% of steel fibers. Various strengths such as tensile strength, compressive strength, flexure strength and modulus of elasticity are determined. In particular for cube different tests such as non-destructive test (NDT), sorptivity, permeability and acid test has been done. It has been observed that the M2 mix (50% of recycled concrete aggregates and dune sand) has produced better results comparatively.

Effect of Mixing Method and Polyvinil Acetate Addition on the Mechanical Properties of Concretes with Recycled Concrete Aggregates

2017 ◽  
Vol 68 (7) ◽  
pp. 1528-1531
Author(s):  
Viorel Craciun ◽  
Dorinel Voinitchi ◽  
Alina Badanoiu ◽  
Radu Voinitchi
Keyword(s):  
Mechanical Properties ◽  
Polyvinyl Acetate ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Mixing Method ◽  
Two Stages ◽  
Mechanical Strengths

The paper presents results regarding the mechanical properties of concretes prepared with various amounts of recycled concrete aggregate (RCA). RCA was obtained by the crushing of concrete rubble resulted during the demolition of a block of flats. The concretes with RCA were prepared using three different mixing approaches: one stage mixing (1SM), two stages mixing (2SM) and two stages mixing with polyvinyl acetate addition (2SM PA). Two stages mixing method in the presence of polyvinyl acetate addition, leads to an improvement of the mechanical strengths (compressive and splitting tensile strength due to a better bonding between the binding matrix formed in the new concrete and the old mortar adhered at the surface of RCA grains.

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