Francisco Agrela

Francisco Agrela
University of Cordoba (Spain) | UCO · Area of construction engineering

Professor

About

74
Publications
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Publications

Publications (74)
Chapter
In recent years, the application of biomass ash in the production of concrete has been the subject of numerous investigations. Several studies have been carried out to apply this type of ash in the manufacturing of concrete as a supplementary cementing material, limestone filler, or replacing natural aggregates. Its use sometimes produces a signifi...
Chapter
In a world where circular economy and zero waste have increasing importance, exploring the potential to transform low value waste residues into a marketable product is essential. Each year industries produce hundreds of thousands of tonnes of process residues that accumulate on site until their eventual disposal. However, some waste residues can be...
Article
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The application of new materials for soil stabilisation is a growing field of study in recent years. In this work, the effect of two types of silica-based nanomaterials combined with binders (quicklime and cement) are studied to stabilise soils and form structural layers for rural and low volume roads. The physical and chemical properties of the ma...
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In recent years, the use of self-compacting concrete has been a great advantage and garnered undoubted interest in construction. Due to the environmental impact caused by the consumption of natural aggregates in the manufacture of concrete, a more sustainable approach is needed. An approach for more sustainable construction is to use industrial was...
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This work develops the manufacture of self-compacting concrete (SCC) with 50% cement reduction. As an alternative binder to cement, the viability of using an alkali-activated combination of stainless steel slag (SSS) and fly ash (FA) has been demonstrated. SSS was processed applying three different treatments. Binders were manufactured mixing 35% S...
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The management of different industrial by-products, such as recycled aggregates from construction and demolition waste and alumina by-products, as well as the reduction of landfill deposits by incorporating these products in a second life cycle, were the focus of this work. The aim of this study was to demonstrate the technical viability of using t...
Chapter
Increased use of concrete in the construction industry worldwide, along with the negative impact of the use of nonrenewable materials such as aggregates and cement for making concrete, has led to a growing production of greener concrete. Excessive use of aggregates depletes natural resources, and inconsiderate quarrying and mining activities to ext...
Chapter
The use of industrial byproducts as construction material can help to achieve sustainability in this industry. Phosphogypsum (PG) is a waste obtained in the phosphoric acid (PA) manufacturing process, produced in large quantities, especially from the soil fertilizer industry. Alternatively, in the disposal of these materials in landfill, several in...
Chapter
Currently a large number of countries have regulated the application of recycled aggregates, steel slag, incineration ashes among others for the manufacture of cement-based materials, as well as the characteristics that recycled aggregate concrete must present. Also, in the past two decades, a labor-intense investigation in this line has been carri...
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In recent years the use of biomass for electricity generation in thermal and cogeneration plants has increased worldwide because it is an environmentally clean fuel whose impact measured in greenhouse gas emissions is practically zero. However, biomass bottom ash, a waste produced during combustion, has also increased considerably, which has both a...
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Stabilization is a traditional strategy used to improve soils with the main objective of ensuring that this base is compliant with the technical specifications required for the subsequent development of different infrastructures. This study proposes the use of commercial nanomaterials, based on a solution of silicates, to improve the technical char...
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The application of recycled aggregates (RA) from construction and demolition waste and crushed concrete blocks is a very important challenge for the coming years from the environmental point of view, in order to reduce the exploitation of natural resources. In Spain, the use of these recycled materials in the construction of road bases and sub-base...
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The volume of slags generated from the steel industry is a source of possible resources which is constantly increasing. Specifically, in the production of stainless steel, specific and singular slags with unique characteristics are obtained, which allows considering an approach aimed at their use in new recycling ways. This work shows the feasibili...
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In the last 15 years, new types of display technologies have increasingly replaced cathode ray tube (CRT) screens, which has led to an increase in landfill of old discarded CRT televisions, which present a great environmental challenge throughout the world due to their high lead content. In addition, environmental awareness has led to greater use o...
Article
El presente proyecto plantea una combinación de las novedosas metodologías docentes: gamificación y aprendizaje cooperativo con el objetivo principal de mejorar la adquisición de competencias en Ingeniería de Proyectos. Todo ello se ha llevado a cabo mediante la elaboración de una práctica audiovisual en formato podcast sin interrupción para su dif...
Presentation
Full-text available
In a world where circular economy and zero waste are taking over, exploring the potentialities to transform a residue into a marketable product is essential. Industrial process residues are very abundant in part due to the fourth industrial revolution currently evolving. The reuse of industrial residues would save natural resources, avoid the cost...
Article
Various treatments of phosphogypsum samples extracted in Huelva, Spain, curing conditions and incorporation ratios were studied to evaluate the viability of being used as set regulator or as supplementary cementitious material to improve the mechanical behaviour of cement mortars. The physical-chemical properties, mechanical behaviour and environme...
Article
Several studies have applied recycled aggregates (RA) in road layers and demonstrated appropriate results. In general, RA can be one of two types: recycled concrete aggregates (RCA) or mixed recycled aggregates (MRA), each of which has lower density, higher water absorption, and lower mechanical strength than natural aggregates (NA). Alumina waste...
Presentation
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Characterisation of industrial wastes for their valorisation as additives in clays for high-attenuation containment barriers. 86-87 pp.
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Construction and Demolition Waste come from debris generated during construction, renovation and demolition of buildings, roads, and bridges. Recycling and reuse are essential in terms of sustainability, mainly from an environmental point of view. Although the recommendation of the use of these recycled aggregates is currently included in some tech...
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Recycled aggregates (RA) have been extensively studied in the production of concrete. Normally, the coarse fraction of recycled concrete aggregates (RCA) is the most commonly used to manufacture recycled concretes. The manufacturing of concrete with fine fraction of RCA and/or recycled mixed aggregates (RMA) (from a mix of concrete, asphalt, masonr...
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Because the recycling of construction and demolition waste (CDW) has been deemed to be a priority, the use of a recycled aggregate has been widely demonstrated as a sustainable contribution among different materials applied in civil projects. Roller compacted concrete (RCC) applications offer technical, economic and ecological solutions in many civ...
Article
This document studies replacing cement by stainless steel slag waste and improving the mechanical properties of the slag waste by using different types of treatments. The application of stainless steel slag waste reduces the use of raw materials for manufacturing cement and provides a profit from the large amount of waste generated. This study anal...
Conference Paper
Phosphogypsum (PG) is an industrial by-product of the fertilizer industry, mainly from the production of phosphoric acid from phosphate rock. PG consists primarily of CaSO4·2H2O, but also contains impurities such as P2O5, F and organic substances, the composition of impurities can be very variable depending on phosphate rock used and other factors...
Article
The use of biomass for power generation is increasingly common. However, one of the most important problems when using biomass is the amount of waste produced in the combustion process such as ash, which must be transported to landfills for deposition. Biomass bottom ash may contain a large amount of organic matter which is the most restrictive pro...
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Full-text available
Biomass is a renewable energy source that is increasingly being used worldwide. However, because of recent increases in production, waste products from biomass combustion are becoming a relevant environmental and economic problem. Other wastes from the construction and demolition sectors have been extensively studied. For this, several research stu...
Article
Two waste streams result from biomass combustion for power generation: biomass fly ash (BFA), which is used as fertilizer in agriculture, and biomass bottom ash (BBA) currently with no practical applications and generally deposited in landfills. This study provides significant information about the mechanical behaviour of mortars made with BBA, and...
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This research is focused on analyzing the environmental pollution potential of biomass bottom ashes as individual materials, as mixtures manufactured with biomass bottom ashes and granular construction aggregates, and these mixtures treated with cement. For the environmental assessment of all of the samples and materials mentioned, the following le...
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This research aims to produce non-structural concrete with mixed recycled aggregates (MRA) in upscaled applications with low-cement content. Four slabs were executed with concrete made with different ratios of coarse MRA (0%, 20%, 40% and 100%), using the mix design, the mixing procedures and the facilities from a nearby concrete production plant....
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In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA) could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i) to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement,...
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Recycled concrete aggregates and mixed recycled aggregates are specified as types of aggregates with lower densities, higher water absorption capacities, and lower mechanical strength than natural aggregates. In this paper, the mechanical behaviour and microstructural properties of natural aggregates, recycled concrete aggregates and mixed recycled...
Conference Paper
Full-text available
The use of recycled aggregates in the manufacture of concrete is increasing significantly mainly due to the need for an environmental solution to this type of material. Therefore, numerous investigations have been performed to study the mechanical properties and durability in concrete made with recycled aggregates from different origins (concrete o...
Conference Paper
Recently, environmental protection has a great concern in world, where recycling of has become a viable option to be incorporated into roads applications. A specific example of this may be the reuse of residues as construction and demolition waste (C&DW) of buildings or bottom ash from biomass (BBA). The topic of the present research is to evaluate...
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Recently, both nationally and internationally, cement-treated granular materials (CTGMs) have been widely used as road base layer. However, all the researches on CTGM with recycled aggregates (RA) are limited to the coarse fraction, with a size range of 0–40 mm. In Spain, one of the recycled materials most commonly produced in construction and demo...
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A focus on environmental sustainability during the last decade has led to greater use of recycled aggregates to reduce the exploitation of existing reserves. In addition, environmentally consciousness has led to an increased use of renewable energy. Biomass is an important source of energy, and it also leads to high generation of waste products fro...
Conference Paper
Cement Treated Granular Material is described as a mixture in which a relatively small amount of cement is used as a binder of coarse aggregates, and which needs proper water content for both compaction and cement hydration. Recycling of demolition debris into new construction offers a way to reduce waste disposal loads sent to area landfills and t...
Conference Paper
Nowadays reusing and valorizing wastes are common actions on managing the residues generated by actual society. A specific example of this may be the reuse of wastes as: steel slags, construction and demolition wastes of buildings or bottom ash from biomass (BBA). All of them have been shown to be suitable for be used in civil engineering infrastru...
Conference Paper
In the last years, power generation of energy from biomass combustion is increasing substantially. Biomass for this type of power generation plants consists essentially of olive residues and other residues from the agricultural industry. However, the combustion of this type of waste produced ashes which must be transported to landfill for depositio...
Conference Paper
Full-text available
Stainless steel production involves today one of the most dynamic sectors of themanufacturing industry, due to a large increase of this product in construction and industrial sector. In this manufacturing process a lot of wastes were generated. For every three tons of stainless steel produced, one ton of slag approximately is generated. In this stu...
Conference Paper
During the last decades, many investigations have been carried out studying the application of Recycled Concrete Aggregates (RCA) from construction and demolition (CDW), in order to manufacture road bases and sub-bases with cement treated granular materials (CTGM) and roller compacted concretes (RCC). The topic of this study is to evaluate the use...
Article
Nowadays it is essential to minimize costs and environmental impact to rehabilitate and construct roads. In the last years there have been numerous studies on the reuse of recycled aggregates in structural layers of road and concrete manufacture. Other types of residues may be applied for these purposes, but currently are taken to landfill or used...
Article
Recycled aggregates from construction and demolition waste have previously been used to manufacture recycled concrete. Generally, these aggregates weaken the physical properties of concrete, such as the density, durability, compressive strength, flexural strength, water penetration, and chloride penetration. This is predominately attributed to the...
Article
The production of energy from renewable resources, such as biomass, is increasing rapidly. Therefore, environmentally friendly and economic solutions to recycle the resulting by-products are essential. The present study was performed to search for possible applications of the biomass bottom ashes that result from biomass combustion at three biomass...
Article
Each year, millions of tonnes of waste are generated worldwide, partially through the construction and demolition of buildings. Recycling the resulting waste could reduce the amount of materials that need to be manufactured. Accordingly, the present work has analysed the potential reuse of construction waste in concrete manufacturing by replacing t...
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Full-text available
Biomass is a renewable energy source that is increasingly being used worldwide. However, because of recent increases in production, waste products from biomass combustion are becoming a relevant environmental and economic problem. In the present research, the technical feasibility of bottom ash from various Andalusian power plants is analysed to ev...
Article
In Spain, there is a low rate of application of recycled aggregates in construction of road bases and sub-bases. Recycled aggregates from crushed concretes (RCA) are usually used as unbound material in road structural layers. Recent studies have confirmed the possibility of applying these RCA in road bases as Cement Treated Granular Material (CTGM)...
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The leaching behaviour of recycled materials from construction and demolition projects needs to be deemed acceptable before they are used for civil infrastructure. The study examines three leaching procedures for characterisation of the potential release of heavy metals and anions regulated by the EU Landfill Directive on seven recycled aggregates...
Chapter
Concrete is widely used as a construction material in buildings and civil works. In the last few years intensive research activity has been carried out on the application of recycled aggregates (RA) to replace natural aggregates (NA) in concrete mixtures. Many investigations have been conducted using different percentages of coarse RA, studying the...
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Full-text available
In the design of shallow foundations normally used in rural buildings on sand, the settlement criterion is more critical than the bearing capacity of the soil. Likewise, it has also been found that widely used methods to estimate the footings settlement on sand, generates differences with the observed in full scale field tests. The aim of this stud...
Article
This paper evaluates the behaviour and the environmental impact of a mixed recycled aggregate from non-selected construction and demolition waste (CDW) in field conditions. For this purpose, one experimental unpaved rural road with two sections was built. Sections were formed with a poor subgrade (A-6) and two structural layers: the first section c...
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In some recycled aggregates applications, such as component of new concrete or roads, the total content of soluble sulphates should be measured and controlled. Restrictions are usually motivated by the resistance or stability of the new structure, and in most cases, structural concerns can be remedied by the use of techniques such as sulphur-resist...
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One of the main applications of recycled aggregates is the construction of sub-bases for roads as unbound materials, substituting for natural aggregates. For this application, recycled aggregates obtained from crushed concrete are mostly used. Nevertheless, in the Mediterranean area, a large amount of mixed (concrete plus masonry) recycled aggregat...
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This article evaluates the behaviour and environmental impact of two recycled aggregates from selected construction and demolition waste (CDW) in field conditions. For this purpose, one experimental unpaved rural road with two sections was built in 2007. Sections were formed with an excellent subgrade (A-1-b) and two structural layers: the first se...
Article
In Spain, the use of recycled aggregates (RA) in the construction of road sub-bases and embankments is growing. Some authors have studied the possibility of using RA in applications with a higher added value, such as the construction of untreated granular sub-bases. However, there is little research on the properties and behaviour of mixed RA treat...
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Construction and demolition wastes are suitable for use in road construction. However, leaching characterization of recycled materials is required to determine their pollutant potential and the consequence of their application in different scenarios. The motivation of this paper is derived from the increasing use of different leaching test methods....