scholarly journals Optimization of High-Performance-Concrete properties containing fine recycled aggregates using mixture design modeling

2021 ◽  
Vol 15 (57) ◽  
pp. 50-62
Author(s):  
Tounsia Boudina ◽  
Dalila Benamara ◽  
Rebih Zaitri
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Pozzolanic Reaction ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Cement Matrix ◽  
Hardened Concrete ◽  
Natural Sand ◽  
Fine Aggregates ◽  
Result Show

This investigation means to predict and modeling the fresh and hardened concrete behavior containing fine aggregates from concrete and brick wastes, for different recycled aggregates substitution rates. To succeed this, the design of experiments DOE method was used. It is observed that slump of recycled concrete is significantly influenced by the content in recycled concrete aggregates (RCA), natural sand (NS) and recycled brick aggregates (RBA), respectively.The compressive strength (CS) reaches a maximum value of 83.48 MPa with factors values of 25% RBA, and 75% RCA. And HPC’s based on RBA sand presented greater values of flexural strength at 7 days than HPC’s based on RCA sand, it was revealed that this is due to the RBA fines pozzolanic reaction and the production of new CSHs, which leads to better cement matrix densification.Under optimal conditions, themaximum desirability is 0.65, who has given HPC no added natural sand, by mixing recycled sands RBA (9.5%) with RCA (90.5%).The statistical terms result show that the expected models are very well correlated with the experimental data and have shown good accuracy.

Microstructural Features of Recycled Aggregate Concrete: From Non-Structural to High-Performance Concrete

2019 ◽  
Vol 25 (3) ◽  
pp. 601-616 ◽  
Author(s):  
Diogo Pedro ◽  
Mafalda Guedes ◽  
Jorge de Brito ◽  
Luís Evangelista
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Sequential Approach

AbstractThe use of concrete-recycled aggregates to produce high-performance concrete is limited by insufficient correlation between resulting microstructure and its influence on mechanical performance reproducibility. This work addresses this issue in a sequential approach: concrete microstructure was systematically analyzed and characterized by scanning electron microscopy and results were correlated with concrete compressive strength and water absorption ability. The influence of replacing natural aggregates (NA) with recycled concrete aggregates (RCA), with different source concrete strength levels, of silica fume (SF) addition and of mixing procedure was tested. The results show that the developed microstructure depends on the concrete composition and is conditioned by the distinct nature of NA, recycled aggregates from high-strength source concrete, and recycled aggregates from low-strength source concrete. SF was only effective at concrete densification when a two-stage mixing approach was used. The highest achieved strength in concrete with 100% incorporation of RCA was 97.3 MPa, comparable to that of conventional high-strength concrete with NA. This shows that incorporation of significant amounts of RCA replacing NA in concrete is not only a realistic approach to current environmental goals, but also a viable route for the production of high-performance concrete.

Effect of Partial Substitution of Fine Aggregate with Copper Slag on Mechanical and Durability of High Performance Concrete-A Review

2020 ◽  
Vol 07 (01) ◽  
pp. 1-11
Author(s):  
Rizwan Ahmad Khan ◽  
Keyword(s):  
Construction Industry ◽  
High Performance ◽  
High Performance Concrete ◽  
Construction Materials ◽  
Copper Slag ◽  
Partial Substitution ◽  
Fine Aggregate ◽  
Natural Sand ◽  
Severe Problem ◽  
Fine Aggregates

The challenge before the construction industry is to meet the demand of the efficient and economically viable construction materials posed by the huge infrastructural needs. Many nations are observing an expeditious growth in the field of construction necessitating the utilization of natural reserves for the expansion of infrastructure. This expansion is giving a warning to available reserves of nature. The natural ingredients, fine aggregates and coarse aggregate constitute more than 70% volume of the concrete. The availability of these resources is decreasing at a very high pace. In fact due to the severe problem with the availability of natural sand, the construction industry is faced with the pressing need to consider available options to lessen the reliance on natural aggregates. Copper slag being a waste material, can be used as an option for fine aggregates. The substitution of fine aggregate from nature with waste materials from industries such as copper slag offers economic and technical dominance, which are of pronounced significance in the present scenario. This study is, based on the critical review of the development of High Performance Concrete (HPC) by replacing fine aggregate with copper slag by observing various other researches and reviews. The key intent of this paper is to closely look at the copper slag utility as an unconventional material to be used as a substitute of fine aggregate and its effect on mechanical and durability parameters of HPC.

A Study on the Use of Construction Wastes as Coarse Aggregates on High Performance Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1525-1531
Author(s):  
Chung Ming Ho ◽  
Wei Tsung Tsai
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Mechanical And Thermal Properties ◽  
Loss On Ignition ◽  
Coarse Aggregates ◽  
Flow Test ◽  
Water To Cement Ratio

In recent years, because of rising consciousness on environmental protection and the lacking of construction waste dumping yards, recycling of construction wastes has been promoted extensively. The purpose of this study is to ascertain the effect on properties of the fresh and harden concrete replacing coarse aggregates by construction wastes under ambient and enhanced temperatures exposure. This research mainly concentrates on high performance recycled concrete (HPRC); by adding different amount of superplasticizer into the HPRC and to test and compare its mechanical and thermal properties with general high performance concrete (HPC). Thereafter, tests are carried out determine its compressive strength, residual strength after high temperature and the loss on ignition of the HPRC mixed with two water-to-cement ratios and different replacement proportions of recycled aggregates. Similar tests, such as the slump test and slump flow test, are carried out both on the HPRC and HPC. When the water-to-cement ratio is 0.3 and the amount of superplasticizer added is 1.2%, HPRC has the best performance. The specimens with 100% recycled aggregates were 31% below the control concrete sample in compressive strength at age of 28 days. By the way of adding admixture, the recycled concrete could reach the demand strength of the HPC. The results show that it is feasible to allow a higher replacement percentage of construction wastes for producing concrete products.

scholarly journals Influence of Recycled High-Performance Aggregate on Deformation and Load-Carrying Capacity of Reinforced Concrete Beams

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 186 ◽  
Author(s):  
Barbara Sadowska-Buraczewska ◽  
Danuta Barnat-Hunek ◽  
Małgorzata Szafraniec
Keyword(s):  
Carrying Capacity ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Recycled Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Load Carrying Capacity ◽  
Load Carrying

The use of recycled concrete aggregates (RCA) in high performance concrete (HPC) was analyzed. The paper presents the experimental studies of model reinforced concrete beams with a rectangular section using high-performance recycled aggregates. Two variable contents of recycled aggregate concrete were used in this study: 50% and 100%. The experimental analyses conducted as immediate studies concerned the following issues: short time loads-deflection, load-carrying capacity of beams, deformation of concrete, cracks, and long-term loads-deflection. The comparative analysis involves the behavior of beams made of high performance concrete-high strength concrete (HPC-HSC) recycled aggregates with model control elements made of regular concrete based on natural aggregates. The deflection values for the recycled aggregate beams were 20% higher than in the case of the control beams made of HPC-HSC exclusively. Replacement of aggregate with recycled concrete aggregate resulted in a large decrease in the value of these two parameters, i.e., compression strength by about 42% and modulus of elasticity by about 33%.

scholarly journals Rheological and Mechanical Properties of Ultra-High-Performance Concrete Containing Fine Recycled Concrete Aggregates

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3717 ◽  
Author(s):  
Lanzhen Yu ◽  
Lili Huang ◽  
Hui Ding
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Deformation Behaviour ◽  
Recycled Concrete ◽  
Ultra High Performance Concrete ◽  
Replacement Rate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Fine Aggregates

The manufacturing process of ultra-high-performance concrete (UHPC) leads to a considerable amount of greenhouse gas emissions, which contribute to global warming. Using recycled concrete aggregates (RCA) to replace natural sand helps to reduce natural resources and energy consumption. In this study, the feasibility of manufacturing UHPC with fine RCA was investigated for the sustainable development of construction materials industry. We aimed to study the rheological properties, autogenous shrinkage, mechanical properties, and pore structure of UHPC with different amounts of RCA. The natural aggregate content was replaced with fine RCA at rates of 0, 20, 40, 60, 80, and 100 wt.%, and the packing density of the mixed fine aggregates in this study was estimated using a linear packing model. It was found that (1) the workability, mechanical properties, and deformation behaviour of UHPC with fine RCA were comparable to or even higher than those of UHPC made of high-quality aggregates; (2) the optimal replacement rate of fine RCA was in the range of 40–60 wt.%, considering the mechanical properties and deformation behaviour of UHPC; (3) the tensile strength, flexural strength, and Young’s modulus of UHPC increased by 6.18%, 12.82%, and 3.40%, respectively, when the replacement rate of fine RCA was 60 wt.%; (4) the maximum packing density of mixed fine aggregates presented a monotonic decreasing trend as the replacement percentage of fine RCA increased. These findings help to encourage and further promote the utilisation of RCA to produce UHPC.

Effect of Copper Slag as a Fine Aggregate on the Durability Characteristics of High-Performance Concrete (HPC) Containing Silica Fume

2020 ◽  
Vol 07 (02) ◽  
pp. 1-10
Author(s):  
Rizwan Ahmad Khan ◽  
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Copper Slag ◽  
Chloride Penetration ◽  
Interfacial Transition Zone ◽  
Fine Aggregate ◽  
Fresh Properties ◽  
Fine Aggregates ◽  
Effect Of Copper

This paper investigates the fresh and durability properties of the high-performance concrete by replacing cement with 15% Silica fume and simultaneously replacing fine aggregates with 25%, 50%, 75% and 100% copper slag at w/b ratio of 0.23. Five mixes were analysed and compared with the standard concrete mix. Fresh properties show an increase in the slump with the increase in the quantity of copper slag to the mix. Sorptivity, chloride penetration, UPV and carbonation results were very encouraging at 50% copper slag replacement levels. Microstructure analysis of these mixes shows the emergence of C-S-H gel for nearly all mixes indicating densification of the interfacial transition zone of the concrete.

scholarly journals Materials for Production of High and Ultra-High Performance Concrete: Review and Perspective of Possible Novel Materials

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4304
Author(s):  
Markssuel Teixeira Marvila ◽  
Afonso Rangel Garcez de de Azevedo ◽  
Paulo R. de de Matos ◽  
Sergio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Review Article ◽  
Cement Matrix ◽  
Bibliographic Databases ◽  
Future Research ◽  
Chemical Additives ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Essential Components

This review article proposes the identification and basic concepts of materials that might be used for the production of high-performance concrete (HPC) and ultra-high-performance concrete (UHPC). Although other reviews have addressed this topic, the present work differs by presenting relevant aspects on possible materials applied in the production of HPC and UHPC. The main innovation of this review article is to identify the perspectives for new materials that can be considered in the production of novel special concretes. After consulting different bibliographic databases, some information related to ordinary Portland cement (OPC), mineral additions, aggregates, and chemical additives used for the production of HPC and UHPC were highlighted. Relevant information on the application of synthetic and natural fibers is also highlighted in association with a cement matrix of HPC and UHPC, forming composites with properties superior to conventional concrete used in civil construction. The article also presents some relevant characteristics for the application of HPC and UHPC produced with alkali-activated cement, an alternative binder to OPC produced through the reaction between two essential components: precursors and activators. Some information about the main types of precursors, subdivided into materials rich in aluminosilicates and rich in calcium, were also highlighted. Finally, suggestions for future work related to the application of HPC and UHPC are highlighted, guiding future research on this topic.

scholarly journals تأثير إستخدام خبث أفران مجموعة جياد الصناعية على جودة الخرسانة

2021 ◽  
Vol 9 (2) ◽  
pp. 1-6
Author(s):  
علي حسين محمد علي ◽  
الطيب عبداللطيف أحمد حبيب
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Hardened Concrete ◽  
Gradual Reduction ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Artificial Materials ◽  
Percent Increase ◽  
And Performance ◽  
Furnace Slag

The need to produce high performance concrete led the researchers to try to exploit the potentialities of natural or artificial materials so as to improve the properties and performance of concrete. Slag is an industrial disposal which considered as a secondary product of pig-iron, these disposal will cause a severe harm to the environment in case of not get rid of it. In this investigation iron furnace slag which is produced at Giad Group - Iron Factory has been used as an alternative of proportion on cement after being processed, since its main oxides are similar to those of cement. In the practical part of our research slag has been added to the concrete mix in two ways, first by using it to replace as cement by weight as a substitutions of cement in different percent [10, 20, 30]% without changing in water-cement ratio [W/C], second by using the slag with the same previous percentage in addition to [15, 25]% to replace cement with reducing in water-cement ratio [W/C], and in addition superplasticizer [SP 901] has been added as percent from cement used in the mixture. The effect of slag was studied on the properties of fresh and hardened concrete including slump test and compressive strength in [7, 14, 28] days were investigated. The results show improvement in all concrete specimens for the added percentage of the slag as replacement materials and the addition of superplasticizer in the production of concrete and improvement in its properties. However, there is a gradual reduction in slump measurements due to slag percent increase in case of the two methods.  

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