scholarly journals PERFORMANCE ASSESSMENT OF A SELF-COMPACTING CONCRETE WITH COARSE AND FINE RECYCLED AGGREGATE

2020 ◽  
Author(s):  
Víctor Revilla-Cuesta ◽  
José Antonio Chica Paez ◽  
José Antonio De la Fuente Alonso ◽  
Estibaliz Briz Blanco ◽  
Jorge Hernández Bagages ◽  
...  
Keyword(s):  
Precast Concrete ◽  
Fine Fraction ◽  
Modern Society ◽  
Coarse Fraction ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Self Compacting Concrete ◽  
Limestone Filler ◽  
Hardened State ◽  
Concrete Elements

Environmental protection and more sustainable human activities are two of the main goals faced by modern society. The reuse of wastes, framed within these objectives, directly affects the construction sector. The use of residues enables to reduce the consumption of natural resources and CO2 emissions released into the atmosphere because of the extractive activity, as well as to reduce potential landfills, thus contributing to a circular economy. Accordingly, this paper explores the development of self-compacting concrete made from high-quality recycled aggregates, obtained from the crushing of precast concrete elements. The replacement rates of the natural aggregate by the recycled aggregate were 100% for the coarse fraction and 50% for the fine fraction. Its validity for structural use is analyzed, both fresh and hardened. In addition, the importance of the limestone filler in the fresh rheology of the mentioned concrete and its impact in the hardened state are also evaluated.

scholarly journals Industrial Low-Clinker Precast Elements Using Recycled Aggregates

2020 ◽  
Vol 10 (19) ◽  
pp. 6655
Author(s):  
Carlos Thomas ◽  
Ana I. Cimentada ◽  
Blas Cantero ◽  
Isabel F. Sáez del Bosque ◽  
Juan A. Polanco
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Precast Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Slight Reduction ◽  
Construction And Demolition Wastes ◽  
Precast Elements ◽  
The Impact ◽  
Concrete Elements

Increasing amounts of sustainable concretes are being used as society becomes more aware of the environment. This paper attempts to evaluate the properties of precast concrete elements formed with recycled coarse aggregate and low clinker content cement using recycled additions. To this end, six different mix proportions were characterized: a reference concrete; 2 concretes with 25%wt. and 50%wt. substitution of coarse aggregate made using mixed construction and demolition wastes; and others with recycled cement with low clinker content. The compressive strength, the elastic modulus, and the durability indicator decrease with the proportions of recycled aggregate replacing aggregate, and it is accentuated with the incorporation of recycled cement. However, all the precast elements tested show good performance with slight reduction in the mechanical properties. To confirm the appropriate behaviour of New Jersey precast barriers, a test that simulated the impact of a vehicle was carried out.

The Influence of Fine Sand from Construction-Demolition Wastes (CDW) in the Mortar Properties

2014 ◽  
Vol 600 ◽  
pp. 357-366 ◽  
Author(s):  
Lidiane Fernanda Jochem ◽  
Janaíde Cavalcante Rocha ◽  
Malik Cheriaf
Keyword(s):  
Fine Fraction ◽  
Fine Sand ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Capillary Absorption ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Natural Sand ◽  
Hardened State

A fine fraction of recycled aggregates from the processing of construction and demolition waste (CDW), have a very effective potential use in mortar as a partial fine aggregate replacement for natural sand, an also contribute to the development of sustainable materials, specifically to produce coating mortar. This paper presents the results of a study using recycled aggregate in mortar as a replacement for natural sand, analyzing the effects of pre-wetting and the performance in mortar composition with a fine sand (1.2/ 0.15 mm). In this study was investigated the behavior of recycled aggregate dry and wet previously until to saturated surface dry condition (reaching this value by capillary absorption test of the granulometric prepared curve). Five different compositions have been defined, varying the quantity of fine and determined the physical properties of recycled aggregate. Then the mortars were prepared and evaluated in the fresh state: specific gravity, water retention and workability, and in the hardened state: hygrothermal and mechanical properties. The results showed that the wetting of the aggregate affects the properties of the mortar, as well the addition of fines. There is an advantage when is realized wetting of the recycled aggregate CDW. The addition of fine in mortars must be controlled, and the fine aggregates improved the almost properties and in excess can reduce the hygrothermals properties.

Durability and Mechanical Properties of Self-Compacting Concrete Incorporating Recovered Filler from Hot Mix Asphalt Plants and Recycled Fine Aggregate

2021 ◽  
Vol 894 ◽  
pp. 95-101
Author(s):  
Sepehr Ghafari ◽  
Fereidoon Moghadas Nejad ◽  
Ofelia Corbu
Keyword(s):  
Compressive Strength ◽  
Hot Mix Asphalt ◽  
Mechanical Performance ◽  
Fine Fraction ◽  
Production Plant ◽  
Fine Aggregate ◽  
Self Compacting Concrete ◽  
Limestone Filler ◽  
Recycled Fine Aggregate ◽  
Maximum Particle

In this research, a sustainable approach is followed to develop efficient mixtures incorporating recycled fine aggregate (RFA) remained from structure demolition as well as limestone filler (LF) from production of hot mix asphalt (HMA). The LF is a byproduct of the drying process in HMA production plant which is not entirely consumed in the production of the HMA and must be hauled and disposed in landfills. The maximum particle size of the LF is approximately 40 µm. Self-Compacting Concrete (SCC) mixtures were designed replacing 5% and 10% of the cement with LF. Incorporation of 50%, and 100% RFA with the fines in the mixtures were considered with and without addition of the LF. Due to the formwork and prefabrication restrictions, the paste volume and the high range water reducer content were tuned in such a way that the slump flow of the mixtures remained between 660 mm to 700 mm without segregation. Durability and mechanical performance of the mixtures were evaluated by resistance against freeze-thaw scaling exposed to deicing agents and compressive strength. It was observed that the SCC mixtures containing 10% LF outperformed those without the use of LF while 5% SCC mixtures did not exhibit tangible superiority. Incorporation of RFA as the fine fraction degraded the durability of all the mixtures. While replacing all the fine fraction with RFA significantly impaired durability and compressive strength, 50% RF mixtures could be designed containing 10% LF that remained in the allowable limits.

A REVIEW ON PERFORMANCE OF WASTE MATERIALS IN SELF COMPACTING CONCRETE (SCC)

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Isham Ismail ◽  
Norwati Jamaluddin ◽  
Shahiron Shahidan
Keyword(s):  
Building Materials ◽  
Recycled Aggregate ◽  
Limestone Powder ◽  
Self Compacting Concrete ◽  
Granulated Blast Furnace Slag ◽  
Materials Research ◽  
Alternative Material ◽  
Hardened State ◽  
Furnace Slag ◽  
Recycled Material

Self-compacting concrete (SCC) was first developed in late 80’s inJapan. SCC is well known for its self-consolidation and able to occupy spaces in the formwork without any vibration and become new interesting topic in Construction and Building Materials Research. There were various SCC researches that have been carried out inTurkey,Malaysia,Thailand,Iran,United Kingdom,Algeria, and India.The aim of this review is to summaries the alternative material used in the mix design from 2009 to 2015 through available literature. It hascommon materials such as Limestone Powder (LP), Fly Ash (FA), Silica Fume and Granulated Blast Furnace Slag (GBFS). While there are many alternative or recycled material can be used in producing SCC. This review only focus on waste material fromMarble Powder (MP), Dolomite Powder (DP), Crump Rubber (CR), Recycled Aggregate (RA) and Rise Husk Ash (RHA).Each type of materialshassimilarity effect in fresh and hardened state of SCC. Therefore, this paper will provide significant and useful information to those new to SCC and fellow researchers for future studies on SCC. 

Structural Integrity Assessment of Precast Concrete Slabs Employing Conventional and Recycled Coarse Aggregates via Vibration Tests

2014 ◽  
Vol 600 ◽  
pp. 504-513 ◽  
Author(s):  
Roberto Leal Pimentel ◽  
Sandro Marden Torres ◽  
Enildo Tales Ferreira ◽  
Aluísio Braz de Melo
Keyword(s):  
Structural Integrity ◽  
Load Capacity ◽  
Precast Concrete ◽  
Damping Ratio ◽  
Limit State ◽  
Load Level ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Impact Excitation ◽  
Integrity Assessment

Precast slabs were tested, consisting of ceramic blocks supported by concrete ribs and with a concrete topping a few centimeters thick. These structures are very common in Brazil, being employed for the construction of houses and small buildings. In one of the tested slabs, recycled coarse aggregate was employed while conventional aggregate (granite gravels and quartz sand) was employed in the other tested slab. This study is part of a broader experimental programme which was designed to assess the applicability of concrete containing recycled aggregates as conventional aggregate replacement. In order to get insight into the structural behavior of slabs with recycled aggregates, the main focus of this paper is to assess the effect of structural load level on vibration parameters (Resonance Frequency, Damping Ratio and Transit Time). Full scale slab structural integrity was assessed by following changes in these parameters via a vibration (modal) test employing impact excitation. The structures were tested for several static load ratios (load to ultimate loading ratios (55%, 82% and 98%)). Visual inspection of induced cracking was also performed. The results obtained indicate a reduction of stiffness in both slabs up to 50% of the stiffness of the respective uncracked structure, which followed a similar trend despite the aggregate types. As for the damping ratios, the recycled aggregate containing slab showed lower values in comparison to the control slab with conventional aggregate. Whereas the former results might indicate similar load capacity, the latter, in principle, may have implications for the vibration serviceability limit state of structures. However, although structures with lower damping ratio can potentially present vibration problems, these studied elements are not often subjected to excessive vibration in its service life.

Study on the Compression Capacity of the Wall of Recycled Aggregates Self-Compacting Rock-Filled Concrete

2013 ◽  
Vol 438-439 ◽  
pp. 719-723
Author(s):  
Hai Chao Wang ◽  
Yi Long Gao ◽  
Xue Hui An
Keyword(s):  
Bearing Capacity ◽  
Testing Machine ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Wall Material ◽  
Self Compacting Concrete ◽  
Concrete Wall ◽  
Mortar Strength ◽  
Deformation Properties

The goal of the paper is to make good use of solid wastes. The aggregates of ordinary self-compacting concrete are changed for the large size of recycled aggregate, which are randomly put into the mold before self-compacting concrete are poured into to form the new type of concrete specimens, and a freestone aggregate specimen is also made for a comparison. 500 tons of electro-hydraulic servo testing machine is used for the test, to measure the strength of this new wall material, bearing capacity, deformation properties and damage form, etc. Test results show that the average compressive strength of the wall of recycled aggregate rock-filled concrete is 6.42MPa, which is far greater than 2.03MPa specified in standard under same mortar strength. Therefore, the recycled aggregate concrete wall of self-compacting has higher bearing capacity, and can meet the requirment of the project.

scholarly journals Effect of Design Parameters on Compressive and Split Tensile Strength of Self-Compacting Concrete with Recycled Aggregate: An Overview

2021 ◽  
Vol 11 (13) ◽  
pp. 6028
Author(s):  
P. Jagadesh ◽  
Andrés Juan-Valdés ◽  
M. Ignacio Guerra-Romero ◽  
Julia M. Morán-del Morán-del Pozo ◽  
Julia García-González ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Fine Aggregate ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Coarse Aggregates ◽  
Fine Aggregates

One of the prime objectives of this review is to understand the role of design parameters on the mechanical properties (Compressive and split tensile strength) of Self-Compacting Concrete (SCC) with recycled aggregates (Recycled Coarse Aggregates (RCA) and Recycled Fine Aggregates (RFA)). The design parameters considered for review are Water to Cement (W/C) ratio, Water to Binder (W/B) ratio, Total Aggregates to Cement (TA/C) ratio, Fine Aggregate to Coarse Aggregate (FA/CA) ratio, Water to Solid (W/S) ratio in percentage, superplasticizer (SP) content (kg/cu.m), replacement percentage of RCA, and replacement percentage of RFA. It is observed that with respect to different grades of SCC, designed parameters affect the mechanical properties of SCC with recycled aggregates.

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 Impact of Design Parameters on the Ratio of Compressive to Split Tensile Strength of Self-Compacting Concrete with Recycled Aggregate

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3480
Author(s):  
Rebeca Martínez-García ◽  
P. Jagadesh ◽  
Gabriel Búrdalo-Salcedo ◽  
Covadonga Palencia ◽  
María Fernández-Raga ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Strength Properties ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Fine Aggregate ◽  
Strength Ratio ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
The Impact

Most concrete studies are concentrated on mechanical properties especially strength properties either directly or indirectly (fresh and durability properties). Hence, the ratio of split tensile strength to compressive strength plays a vital role in defining the concrete properties. In this review, the impact of design parameters on the strength ratio of various grades of Self-Compacting Concrete (SCC) with recycled aggregate is assessed. The design parameters considered for the study are Water to Cement (W/C) ratio, Water to Binder (W/B) ratio, Total Aggregates to Cement (TA/C) ratio, Fine Aggregate to Coarse Aggregate (FA/CA) ratio, Water to Solid (W/S) ratio in percentage, superplasticizer (SP) content (kg/cu.m), replacement percentage of recycled coarse aggregates (RCA), replacement percentage of recycled fine aggregates (RFA), fresh density and loading area of the specimen. It is observed that the strength ratio of SCC with recycled aggregates is affected by design parameters.

scholarly journals Recycled Precast Concrete Kerbs and Paving Blocks, a Technically Viable Option for Footways

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7007
Author(s):  
Andrés Juan-Valdés ◽  
Desirée Rodríguez-Robles ◽  
Julia García-González ◽  
María Isabel Sánchez de Rojas ◽  
Manuel Ignacio Guerra-Romero ◽  
...  
Keyword(s):  
Water Absorption ◽  
Circular Economy ◽  
Precast Concrete ◽  
Research Work ◽  
Lower Class ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Durability ◽  
Conventional Concrete

The linear economy paradigm in place to date has to be seriously challenged to give way to a new school of thought known as the circular economy. In this research work, precast kerbs and paving blocks made with recycled concrete (RACC-mixture) bearing 50 wt% mixed recycled aggregate (masonry content of 33%) and an eco-efficient cementitious material as 25 wt% conventional binder replacement were evaluated to assess their intrinsic potential to replace traditional raw materials, in keeping with circular economy criteria. Therefore, precast products were subjected to mechanical strength, durability and microstructure tests and were compared to conventional concrete units (CC-mixture and commercially available precast elements). Although a class demotion was observed for water absorption and some decreases in flexural strength (26%), splitting tensile strength (12.8%) and electrical resistivity (45%) and a lower class water absorption were registered, and the recycled mixture also exhibited a greater performance in terms of compressive strength (6%), a better abrasion resistance classification and a comparable porosity and microstructure, which ensures a good concrete durability. In any case, the results showed that precast pieces were European standard-compliant, thus supporting the viability of the mixed recycled aggregates and eco-efficient cementitious replacement in footways.

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