scholarly journals Utilization of Recycled Concrete Aggregates in Stone Mastic Asphalt Mixtures

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad Saeed Pourtahmasb ◽  
Mohamed Rehan Karim
Keyword(s):  
Design Method ◽  
Recycled Concrete ◽  
Engineering Properties ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregates ◽  
Material Recycling ◽  
Mastic Asphalt ◽  
Fine Aggregates ◽  
Stone Mastic Asphalt

Recycled concrete aggregate (RCA) is considered as one of the largest wastes in the entire world which is produced by demolishing concrete structures such as buildings, bridges, and dams. It is the intention of scientists and researchers, as well as people in authority, to explore waste material recycling for environmental and economic advantages. The current paper presents an experimental research on the feasibility of reusing RCA in stone mastic asphalt (SMA) mixtures as a partial replacement of coarse and fine aggregates. The engineering properties of SMA mixtures containing RCA have been evaluated for different percentages of binders based on the Marshall mix design method. The outcomes were statistically analyzed using two-factor analysis of variance (ANOVA). Test results revealed that the performance of SMA mixtures is affected by RCA due to higher porosity and absorption of RCA in comparison with virgin granite aggregates. However, the engineering properties of SMA mixtures containing a particular amount of RCA showed the acceptable trends and could satisfy the standard requirements. Moreover, to achieve desirable performance characteristics, more caution should be made on properties of SMA mixtures containing RCA.

scholarly journals Slope Stability Analysis of Recycled Concrete Fine Aggregate Stabilized and Blended Soils

2020 ◽  
Vol 9 (5) ◽  
pp. 991-994
Keyword(s):  
Limit Equilibrium ◽  
Recycled Concrete ◽  
Engineering Properties ◽  
Cement Kiln ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Fine Aggregates ◽  
Kiln Dust

Recycled concrete aggregate (RCA) is one of the major material generated from municipal soild waste industry. In the current study, recycled concrete aggregates are collected from the demolished building. The index and engineering properties of crushed concrete and locally available soil are determined. The study aims at effective reuse of demolition concrete waste as backfill of earth retaining walls. RCA passing through 4.75mm is stabilized by using Cement kiln dust (CKD) and Fly Ash (FA) in various proportions. Red soil is partially replaced by 30%, 50%, and 70% with recycled concrete fine aggregates. A numerical model is developed using limit equilibrium software i.e GeoStudio Slope/w. It is found that 15% CKD and 15% FA is optimum to stabilize the material. In case of blended soils, 30% replacement with RC-FA is found to be optimum

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 Evaluation of Mechanical Characteristics of Cement Mortar with Fine Recycled Concrete Aggregates (FRCA)

2021 ◽  
Vol 13 (1) ◽  
pp. 414
Author(s):  
Rebeca Martínez-García ◽  
María Isabel Sánchez de Rojas ◽  
Julia Mª. Morán-del Pozo ◽  
Fernando J. Fraile-Fernández ◽  
Andrés Juan-Valdés
Keyword(s):  
Research Work ◽  
Chemical Characterization ◽  
Recycled Concrete ◽  
Partial Replacement ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Fine Aggregates ◽  
Simple Processing ◽  
Processing Techniques ◽  
Physical And Chemical

One of the growing demands in concrete manufacture is the availability of natural fine aggregates, which account for 35% to 45% of the total concrete. An alternative method of disposal of fine recycled concrete aggregates (FRCA) generated from demolition and construction waste (C&DW) is their usage in mortar and the development of recycled mortar. The main aim of this research work is to evaluate the viability of incorporating FRCA from urban C&DW for the manufacture of cement-based mortars. Simple processing techniques like washing and sieving are adopted to improve the FRCA quality. Physical and chemical characterization of ingredients is carried out. In total four mixes of 1:3 (cement: sand) mortar with partial replacement of normalized sand with FRCA (0%, 25%, 50%, and 100%) are evaluated for mechanical properties. Water to cement ratio for all four mortar mixes are determined by fixed consistency. Mechanical and physical properties like density, compressive strength, and flexural strength are studied for various curing periods, and the result is that the optimum usage of FRCA is 25% based on a 90-day curing period.

scholarly journals Structural Use of Expanded Polystyrene Concrete

2020 ◽  
Vol 5 (6) ◽  
pp. 1131-1138
Author(s):  
Adeniran Jolaade ADEALA ◽  
Olugbenga Babajide SOYEM
Keyword(s):  
Environmental Pollution ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
Consumer Products ◽  
Expanded Polystyrene ◽  
Engineering Properties ◽  
Partial Replacement ◽  
Construction Companies ◽  
Fine Aggregates ◽  
Concrete Matrix

Expanded polystyrene (EPS) wastes are generated from industries and post-consumer products. They are non-biodegradable but are usually disposed by burning or landfilling leading to environmental pollution. The possibility of using EPS as partial replacement for fine aggregates in concrete has generated research interests in recent times. However, since the physical and mechanical properties of EPS are not like those of conventional fine aggregates, this study is focussed on the use of EPS as an additive in concrete while keeping other composition (sand and granite) constant. Expanded polystyrene was milled, the bulk density of EPS was 10.57kg/m3 and particle size distributions were determined. Engineering properties of expanded polystyrene concrete were determined in accordance with BS 8110-2:1985. The result showed that the amount of expanded polystyrene incorporated in concrete influence the properties of hardened and fresh concrete. The compressive strengths of 17.07MPa with 5 % expanded polystyrene concrete at 28 days for example can be used as a lightweight concrete for partitioning in offices. Incorporating expanded polystyrene granules in a concrete matrix can produce lightweight polystyrene aggregate concrete of various densities, compressive strengths, flexural strengths and tensile strengths. In conclusion, this reduces environmental pollution, reduction in valuable landfill space and also for sustainability in construction companies

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.

scholarly journals Effects of pre-wetting aggregate on the properties of mortars made with recycled concrete and lightweight aggregates

2019 ◽  
Vol 24 (2) ◽  
Author(s):  
Lidiane Fernanda Jochem ◽  
Diego Aponte ◽  
Marilda Barra Bizinotto ◽  
Janaíde Cavalcante Rocha
Keyword(s):  
Lightweight Aggregate ◽  
Heat Of Hydration ◽  
Recycled Concrete ◽  
Partial Replacement ◽  
Dry Density ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Natural Aggregate ◽  
Entrained Air ◽  
Dimensional Instability

ABSTRACT This paper examines the suitability of partially replacing natural aggregate, sand, (NA) with recycled concrete aggregate (RCA) or lightweight aggregate (LWA) in mortars, under the hypothesis that pre-wetting aggregates would produce improvement in mortar properties. Fresh mortar properties such as density, entrained air content, consistency and heat of hydration, as well as hardened mortar properties such as dry density, compressive and flexural strength, and dimensional instability at 0% and 100% saturation were determined. The results show that mortars made with natural aggregate (75%) and recycled concrete aggregate (25%) have similar properties to mortars made with only natural aggregate (100%) and that pre-wetting the aggregates does not influence the properties of mortars significantly. Therefore, partial replacement with recycled concrete aggregate is a viable alternative for producing mortar.

Review of Studies concerning Effects of Unbound Crushed Concrete Bases on PCC Pavement Drainage

1996 ◽  
Vol 1519 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Mark B. Snyder ◽  
James E. Bruinsma
Keyword(s):  
Drainage System ◽  
Field Studies ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Drainage Systems ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Crushed Concrete ◽  
Pavement Structures ◽  
Natural Aggregates

Recycled concrete aggregate (RCA) products are sometimes used as replacements for virgin aggregate products in concrete pavement structures. Recent concerns have centered on the deposit of RCA-associated fines and precipitate suspected of reducing the drainage capacity of RCA base layers and associated drainage systems. Environmental concerns have focused on the relatively high pH of the effluent produced by untreated RCA base layers. Several studies have examined these concerns and others; the results of some of these studies have not been published or publicized. The most relevant of these studies are summarized herein. These research efforts demonstrate that calcium-based compounds are present in most recycled concrete aggregates in quantities sufficient to be leached and precipitated in the presence of carbon dioxide. Precipitate potential appears to be related to the amount of freshly exposed cement paste surface. Thus, selective grading or blending with natural aggregates can reduce, but not eliminate, precipitate problems. It was also noted that insoluble, noncarbonate residue makes up a major portion of the materials found in and around pavement drainage systems. Washing the RCA products before using them in foundation layers appears to reduce the potential for accumulation of dust and other fines in the drainage system, but probably has little effect on precipitate potential. Field studies have shown that precipitate and insoluble materials can significantly reduce the permittivity of typical drainage fabrics but that attention to drainage design details can minimize the effects of these materials on pavement drainage.

scholarly journals Mechanical and Durability Properties of Cement-Stabilized Recycled Concrete Aggregate

2020 ◽  
Vol 12 (18) ◽  
pp. 7380
Author(s):  
Qingfu Li ◽  
Jing Hu
Keyword(s):  
Cement Content ◽  
Drying Shrinkage ◽  
Recycled Concrete ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Curing Time ◽  
Recycled Concrete Aggregate ◽  
Replacement Ratio ◽  
Obvious Effect ◽  
Study Test

This research investigates the effect of using recycled concrete aggregate (RCA) as a partial replacement of natural aggregate (NA) on the mechanical and durability-related properties of a cement-stabilized recycled concrete aggregate (CSR) mixture. In this case, mixtures were prepared with 0%, 40%, 70%, and 100% (by weight) RCA to replace NA, and cement contents of 4%, 5%, and 6% were used in this study. Test parameters included the replacement ratio, cement content, and curing time. Tests were carried out to establish the unconfined compressive strength (UCS), indirect tensile strength (ITS), drying shrinkage, and water loss ratio of each mix proportion. The preliminary results of UCS and ITS tests indicated that the incorporation of RCA resulted in a decrease of strength compared with a cement-stabilized macadam (CSM) mixture, but the seven-day strength of the CSR mixture met the related requirements of road bases. The increase in cement content and curing time had an obvious effect on strength improvement. The drying shrinkage test showed that the drying shrinkage properties of the CSR mixture were obviously reduced with a high replacement ratio. It is evident that the CSM mixture presented a better drying shrinkage performance than that of the CSR mixture.

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