scholarly journals Durability Assessment of Recycled Aggregate HVFA Concrete

2020 ◽  
Vol 10 (18) ◽  
pp. 6454
Author(s):  
Valeria Corinaldesi ◽  
Jacopo Donnini ◽  
Chiara Giosué ◽  
Alessandra Mobili ◽  
Francesca Tittarelli
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Corrosion Behavior ◽  
High Volume ◽  
Recycled Aggregate Concrete ◽  
Galvanized Steel ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
High Volume Fly Ash ◽  
Natural Aggregates

The possibility of producing high-volume fly ash (HVFA) recycled aggregate concrete represents an important step towards the development of sustainable building materials. In fact, there is a growing need to reduce the use of non-renewable natural resources and, at the same time, to valorize industrial by-products, such as fly ash, that would otherwise be sent to the landfill. The present experimental work investigates the physical and mechanical properties of concrete by replacing natural aggregates and cement with recycled aggregates and fly ash, respectively. First, the mechanical properties of four different mixtures have been analyzed and compared. Then, the effectiveness of recycled aggregate and fly ash on reducing carbonation and chloride penetration depth has been also evaluated. Finally, the corrosion behavior of the different concrete mixtures, reinforced with either bare or galvanized steel plates, has been evaluated. The results obtained show that high-volume fly ash (HVFA) recycled aggregate concrete can be produced without significative reduction in mechanical properties. Furthermore, the addition of high-volume fly ash and the total replacement of natural aggregates with recycled ones did not modify the corrosion behavior of embedded bare and galvanized steel reinforcement.

scholarly journals Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

2018 ◽  
Vol 8 (7) ◽  
pp. 1189 ◽  
Author(s):  
Rawaz Kurda ◽  
Jorge de Brito ◽  
José Silvestre
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Mechanical Characteristics ◽  
High Volume ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Strength Development ◽  
Economic Point ◽  
The Cost

This study intends to evaluate high and low-strength concrete mixes made with high volume of fly ash (FA) and recycled concrete aggregates (RCA) from both a mechanical and economic point of view. For this purpose, the mechanical characteristics of concrete, namely compressive strength (fcm), splitting tensile strength (fctm), and modulus of elasticity (Ecm) were correlated with the cost of 1 m3 of concrete mixes, taking into account the most common scenarios (e.g., cost of the raw materials, transportation between supplier and concrete plant, and mixing procedure) in the centre of Portugal. The results show that the incorporation of FA and RCA are detrimental to the mechanical properties of concrete. Ecm is predominantly influenced by RCA, and “fcm” and “fctm” are mainly controlled by FA incorporation. However, after a given age, the rate of the strength development (fcm, fctm and Ecm) of RCA concrete containing FA significantly accelerates over time relative to the reference concrete (without FA and RCA) and to the mixes made with either RCA or FA. Furthermore, the cost of concrete does not significantly change by incorporating RCA. The use of superplasticizer (SP) significantly increases the cost of concrete. However, the higher cost of concrete due to the use of SP can be offset by replacing cement with FA. Regarding the optimization process, concrete mixes with the lowest cost may not necessarily be the optimum choice regarding cost efficiency. In fact, the mechanical properties of concrete also need to be considered to aid the decision on the optimal concrete mix. Finally, the results show that the optimum mixes in terms of cost and mechanical characteristics are mostly the ones made with simultaneous incorporation of RCA, FA, and SP, rather than with their individual incorporation.

The Mechanical Properties of Recycled Aggregate Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1852-1855
Author(s):  
Zuo Shan Li ◽  
Li Hui Xie ◽  
Jun Ya Luo ◽  
Xiang Chao Zhang
Keyword(s):  
Mechanical Properties ◽  
Laboratory Experiments ◽  
Building Materials ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Hardened Concrete ◽  
Preparation Process ◽  
Aggregate Concrete ◽  
Waste Concrete ◽  
Natural Aggregates

The experimental investigation of the preparation process of recycled aggregate concrete (RAC) using the waste concrete as recycled aggregate concrete (RCA) was reported. By conducting a series of laboratory experiments, the crushing and sieving procedure of wasted concrete to produce RCA were studied, the RACs with different strengths were designed, the strengths of hardened concrete were investigated. The results indicated that the representative strength for designing C10, C15 and C25 grade RAC using RCA were 11.3, 16.2 and 27.3 Mpa, respectively. The results gained in this study prove to be a valuable building materials using RCA for doveloping the RAC. Recycling and reuse of building wastes have been found to be an appropriate solution to the problems of dumping hundred of thousands tons of debris accompanied with shortage of natural aggregates.

scholarly journals Effect of Aggregate Size on Recycled Aggregate Concrete under Equivalent Mortar Volume Mix Design

2021 ◽  
Vol 11 (23) ◽  
pp. 11274
Author(s):  
Haneol Jang ◽  
Jeonghyun Kim ◽  
Alena Sicakova
Keyword(s):  
Mechanical Properties ◽  
Distribution Curve ◽  
Aggregate Size ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Particle Size Distribution Curve ◽  
Aggregate Concrete ◽  
Natural Aggregates

In this paper, the effect of the original aggregate size of the recycled aggregate on the mechanical properties of the recycled aggregate concrete was evaluated. A series of concretes were produced in which natural aggregates, recycled aggregates, and original aggregates in recycled aggregates were matched for a single particle size distribution curve. The replacement levels of recycled aggregate were 25% and 50%, and equivalent mortar volume mix design was applied for recycled aggregate concrete. The results show that the mechanical strength of recycled aggregate concrete increases with increasing original aggregate size. This effect was observed to be greater in concrete using recycled aggregate with a high residual mortar content.

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