Mortars with CDW Recycled Aggregates Submitted to High Levels of CO2

Construction and demolition wastes (CDW) are generated at a large scale and have a diversified potential in the construction sector. The replacement of natural aggregates (NA) with CDW recycled aggregates (RA) in construction materials, such as mortars, has several environmental benefits, such as the reduction in the natural resources used in these products and simultaneous prevention of waste landfill. Complementarily, CDW have the potential to capture CO2 since some of their components may carbonate, which also contributes to a decrease in global warming potential. The main objective of this research is to evaluate the influence of the exposure of CDW RA to CO2 produced in cement factories and its effect on mortars. Several mortars were developed with a volumetric ratio of 1:4 (cement: aggregate), with NA (reference mortar), CDW RA and CDW RA exposed to high levels of CO2 (CRA). The two types of waste aggregate were incorporated, replacing NA at 50% and 100% (in volume). The mortars with NA and non-carbonated RA and CRA from CDW were analysed, accounting for their performance in the fresh and hardened states in terms of workability, mechanical behaviour and water absorption by capillarity. It was concluded that mortars with CDW (both CRA and non-carbonated RA) generally present a good performance for non-structural purposes, although they suffer a moderate decrease in mechanical performance when NA is replaced with RA. Additionally, small improvements were found in the performance of the aggregates and mortars with CRA subjected to a CO2 curing for a short period (5 h), while a long carbonation period (5 d) led to a decrease in performance, contrary to the results obtained in the literature that indicate a significant increase in such characteristics. This difference could be because the literature focused on made-in-laboratory CDW aggregates, while, in this research, the wastes came from real demolition activities, and were thus older and more heterogeneous.

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Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

Sustainability ◽

10.3390/su13052756 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2756

Author(s):

Federica Vitale ◽

Maurizio Nicolella

Keyword(s):

Building Materials ◽

Thermal Analyses ◽

Construction Materials ◽

Physical And Mechanical Properties ◽

Research Trends ◽

Mix Design ◽

Recycled Aggregates ◽

Design Parameters ◽

Natural Aggregates ◽

By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

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Mechanical Performance of Asphalt Mixtures with Natural Aggregates and Recycled Aggregates for Surface Course

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.600.657 ◽

2014 ◽

Vol 600 ◽

pp. 657-666 ◽

Cited By ~ 1

Author(s):

Vagner da Costa Marques ◽

Bismak Oliveira de Queiroz ◽

Diego Meira de Lacerda ◽

Antônio Marcos de Araújo Gouveia ◽

Ricardo Almeida de Melo

Keyword(s):

Solid Waste ◽

Environmental Impacts ◽

Mechanical Performance ◽

Waste Recycling ◽

Asphalt Mixtures ◽

Recycled Concrete ◽

Recycled Aggregates ◽

Asphalt Mix ◽

Natural Aggregates ◽

Marshall Stability

The recycled aggregates of construction and demolition solid waste can be used on pavements to decrease environmental impacts in cities. Thus, this study aimed to compare the mechanical performance of asphaltic mixtures made with natural aggregates and concrete recycled aggregates for surface course of pavements. The materials were collected in an asphalt mixing plant and in a construction and demolition solid waste recycling plant located in João Pessoa/PB, Brazil. The Marshall asphalt mix design was chosen to determine optimum asphalt content and evaluate mechanical performance of asphaltic mixtures. The asphalt mixtures specimens were composed of natural aggregates, and afterwards of recycled aggregates with percent contents of 25, 50 and 100. The optimum asphalt contents were 5.7 and 7.5%, Marshall stability of 1,070 and 790 Kgf, flow of 6.2 and 5.7 mm for natural aggregate asphalt mixtures and asphalt mixtures with 25% recycled aggregates, respectively. Moreover, percent air voids and percent voids filled with asphalt met the Brazilian DNIT: ES 031/2006 specified standard. However, the asphalt mixtures with 50 and 100% recycled aggregates did not meet the specified standard. Therefore, it was concluded that the replacement of natural aggregates with 25% recycled concrete aggregates in asphalt mixtures can be technically viable to build asphalt surface course on pavements, besides lowering pavement costs and decreasing environmental impacts.

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Preparation and Characterization of the Functional Properties of Synthetic Aggregates from Silico-Manganese Slag

Materials ◽

10.3390/ma14237303 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7303

Author(s):

Zhibing Xing ◽

Fenglan Han ◽

Jiuliang Tian ◽

Zhichao Xu ◽

Jiaqi Wang ◽

...

Keyword(s):

Fly Ash ◽

Large Scale ◽

Construction Materials ◽

Raw Material ◽

Curing Temperature ◽

Fixed Amount ◽

Aggregate Properties ◽

Alkaline Activator ◽

Natural Aggregates ◽

Cold Bonding

A large number of natural aggregates are used in the field of construction materials, resulting in the exhaustion of natural aggregates. Therefore, looking for an alternative will slow down the consumption of natural aggregates. The sintering method not only consumes a lot of energy to prepare aggregates but also produces a lot of pollutants. In this study, silico-manganese (SM) slag was dried, ground into powder, and used as raw material. Solid and liquid alkaline activator methods were used to prepare SM slag non-burning aggregate (SMNA) by the cold bonding method. The effects of grinding time, amounts of solid and liquid alkaline activators, curing temperature, and the amount of added fly ash on aggregate properties were investigated. The aggregate microstructure was characterized by XRD, SEM, and FTIR methods, and the toxic leaching analysis of aggregate was performed. The results showed that with a fixed amount of liquid activator (16.2% wt.) and solid activator (15% wt.) and fly ash (20% wt.), respectively, and curing was performed at room temperature, the aggregate properties were optimal: the bulk density of 1236.6–1476.9 kg/m3 and the water absorption lower than 4.9–5.5%. The apparent density was 1973.1–2281.6 kg/m3, and the bulk crushing strength was 24.7–27.9 MPa. The XRD, SEM, and FTIR results indicated that amorphous gel could be formed from SM under an alkaline activator, improving the aggregate strength. The results of toxic leaching showed that the aggregate prepared from SM exhibited environmentally friendly characteristics. The SMNA was obtained via the simple and low-energy consumption production process, paving the new way toward large-scale utilization of SM.

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Reuse of improved recycled concrete aggregates (RCA) for sustainable and environmental-friendly construction materials.

10.21203/rs.3.rs-48821/v2 ◽

2021 ◽

Author(s):

Ahmad Sarhan Alyaseen ◽

Siddharth Shah ◽

Ravindra Solanki ◽

Bhavik Daxini ◽

Yogesh K. Alwani ◽

...

Keyword(s):

Acetic Acid ◽

Industrial Development ◽

Waste Treatment ◽

Acetic Acid Solution ◽

Construction Materials ◽

Road Construction ◽

Recycled Concrete ◽

Recycled Aggregates ◽

Recycled Concrete Aggregates ◽

Natural Aggregates

Abstract Recycled aggregates have an essential role in constructing construction activities today to save natural aggregates because of industrial development. The research aims to assess the suitability of recycled aggregates for the construction of new roads, which will help achieve road construction efficiency and help prevent environmental deterioration in the extraction and reducing pollution. In contrast with natural aggregates, recycled aggregates are of lower quality, mainly due to the cement mortar's brittle nature attached to them. The point of the study is to increase the performance of RCAs in an environmentally friendly managing RCAs. In this process, RCAs are first soaked in acetic acid solution, in which acetic acid reacts with cement attached to the surface of the RCA. This reaction weakens the attached mortar and allows separating from the RCAs by using mechanical friction later. Treated RCAs have lower water absorption and more insufficient cement mortar adhesion. These RCAs used as aggregates in new the concrete increased the compressive strength, the tensile strength, and the concrete's flexural strength by 26%, 11%, and 26% at 28 days, respectively. It is clean, safe, efficient, and a new method to be applied, so no harmful products are used, and no dangerous substances are incorporated into the RCAs that are being treated. The waste treatment solution was used as a supplementary admixture construction, increasing the concrete's strength, and decreasing its environmental effects.

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Water sludge: utilization in the production of construction materials and agriculture Alternative coagulants (a review)

Vodosnabzhenie i sanitarnaia tehnika ◽

10.35776/mnp.2020.06.08 ◽

2020 ◽

Author(s):

В.Я. Кофман

Keyword(s):

Construction Industry ◽

Large Scale ◽

Raw Materials ◽

Construction Materials ◽

Wastewater Sludge ◽

Sludge Disposal ◽

Agricultural Use ◽

Tree Seeds ◽

Moringa Oleifera Oil ◽

Made In

При производстве строительных материалов и в сельском хозяйстве могут быть использованы значительные объемы водопроводных осадков, обеспечивая при этом их утилизацию. Следствием применения осадков в строительной промышленности может стать существенная экономия традиционных сырьевых материалов без ухудшения качества продукции. Налаженных поставок водопроводных осадков на предприятия стройиндустрии, однако, пока не происходит, и в качестве основной причины называют непостоянство их состава. Вместе с тем достигнутые результаты свидетельствуют о значительных усилиях, предпринимаемых в этой области. На основе использования водопроводных осадков разработаны технологии производства цемента, строительного раствора, бетона, кирпича, кровельной черепицы, керамических изделий. Сельскохозяйственное применение водопроводных осадков считается наиболее доступным и масштабным вариантом их утилизации. Содержание органики и тяжелых металлов в водопроводных осадках достаточно ограниченно, что выгодно отличает их от осадков сточных вод и позволяет классифицировать как безопасные. К настоящему времени в целом ряде стран проведены многолетние масштабные эксперименты по использованию водопроводных осадков для корректировки содержания растворимого фосфора в почвах, для связывания растворимых форм мышьяка и хрома и корректировки содержания микроэлементов. Кардинальное решение проблемы водопроводных осадков должно быть связано с уменьшением их образования в процессе водоподготовки. В этом направлении ведется поиск альтернативных коагулянтов, прежде всего растительного происхождения. Достигнутые результаты позволили провести опытно-промышленные испытания водного экстракта семян масличного дерева Moringa oleiferaв качестве коагулянта при очистке поверхностной воды. Utilization of water sludge in significant amounts can be provided by using it in the production of construction materials and in agriculture. The use of water sludge in the construction industry can result in significant savings in traditional raw materials without compromising product quality. However, the supply of water sludge to the construction industry enterprises, has not been established so far, and the instability of its composition is posed as the main reason. At the same time, the results achieved evidence significant efforts made in this area. Based on the use of water sludge, technologies have been developed for the production of cement, building mortar, concrete, brick, roofing tiles, and ceramic products. Agricultural use of water sludge is considered as a most affordable and large-scale option of its disposal. The concentration of organics and heavy metals in water sludge is quite limited, which sets it apart from wastewater sludge and allows it being classified as safe. To date, in a number of countries many years of large-scale experiments have been conducted on the use of water sludge for adjusting the concentration of soluble phosphorus in soils; binding soluble forms of arsenic and chromium, and adjusting the concentration of trace elements. A radical solution to the problem of water sludge disposal should be associated with reducing its amount generated during water purification process. In this direction, studies are being conducted on alternative coagulants, primarily of plant origin. The results achieved made it possible to carry out pilot tests of using aqueous extract of Moringa oleifera oil-tree seeds as a coagulant in the purification of surface water.

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Cumulative metal leaching from utilisation of secondary building materials in river engineering

Water Science & Technology ◽

10.2166/wst.2004.0195 ◽

2004 ◽

Vol 49 (3) ◽

pp. 197-203 ◽

Cited By ~ 4

Author(s):

R.S.E.W. Leuven ◽

F.H.G. Willems

Keyword(s):

Surface Waters ◽

Large Scale ◽

Building Materials ◽

Steel Slag ◽

Environmental Benefits ◽

Water Quality Standards ◽

Demolition Waste ◽

Engineering Structures ◽

Leaching Models ◽

Made In

The present paper estimates the utilisation of bulky wastes (minestone, steel slag, phosphorus slag and demolition waste) in hydraulic engineering structures in Dutch parts of the rivers Rhine, Meuse and Scheldt over the period 1980-2025. Although they offer several economic, technical and environmental benefits, these secondary building materials contain various metals that may leach into river water. A leaching model was used to predict annual emissions of arsenic, cadmium, copper, chromium, lead, mercury, nickel and zinc. Under the current utilisation and model assumptions, the contribution of secondary building materials to metal pollution in Dutch surface waters is expected to be relatively low compared to other sources (less than 0.1% and 0.2% in the years 2000 and 2025, respectively). However, continued and widespread large-scale applications of secondary building materials will increase pollutant leaching and may require further cuts to be made in emissions from other sources to meet emission reduction targets and water quality standards. It is recommended to validate available leaching models under various field conditions. Complete registration of secondary building materials will be required to improve input data for leaching models.

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Current Applications of Recycled Aggregates from Construction and Demolition: A Review

Materials ◽

10.3390/ma14071700 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1700

Author(s):

Glaydson Simões dos Reis ◽

Marco Quattrone ◽

Weslei Monteiro Ambrós ◽

Bogdan Grigore Cazacliu ◽

Carlos Hoffmann Sampaio

Keyword(s):

Raw Materials ◽

Construction Materials ◽

Cementitious Materials ◽

Construction And Demolition Waste ◽

Recycled Aggregates ◽

Demolition Waste ◽

Construction Engineering ◽

New Construction ◽

Natural Aggregates ◽

Environmentally Friendly Approach

A literature review comprising 163 publications published over a period of 26 years from 1992 to 2018 is presented in this paper. This review discusses the generation and recycling of construction and demolition waste (CDW) as well as its main uses as raw materials for the construction engineering sector. This review pays attention to the use of CDW aggregates for sand, pavements/roads, bricks, ceramics, cementitious materials, and concrete productions, as well its uses as eco-friendly materials for water decontamination. The physical-chemical and mechanical characteristics of recycled aggregates play an important role in their correctly chosen applications. The results found in this literature survey allow us to conclude that recycled aggregates from CDW can be successfully used to produce construction materials with quality comparable to those produced with natural aggregates. We concluded that the use of CDWs as raw materials for manufacturing new construction materials is technically feasible, economical, and constitutes an environmentally friendly approach for a future construction and demolition waste management strategy.

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A Laboratory Assessment of the Influence of Crumb Rubber in Hot Mix Asphalt with Recycled Steel Slag

Sustainability ◽

10.3390/su12198045 ◽

2020 ◽

Vol 12 (19) ◽

pp. 8045 ◽

Cited By ~ 1

Author(s):

Bruno Crisman ◽

Giulio Ossich ◽

Lorenzo De Lorenzi ◽

Paolo Bevilacqua ◽

Roberto Roberti

Keyword(s):

Asphalt Concrete ◽

Steel Slag ◽

Fatigue Cracking ◽

Crumb Rubber ◽

Environmental Benefits ◽

Production Costs ◽

Recycled Aggregates ◽

Slight Reduction ◽

Cyclic Loads ◽

Natural Aggregates

To reduce thermal susceptibility and improve rutting and fatigue cracking resistance, increasingly more non-conventional additives and materials have been used in road pavement asphalt mixes in recent years. Non-conventional materials mainly include recycled materials, which reduce production costs and lead to environmental benefits related to their reuse. The aim of this research was to evaluate the influence of recycled tyre rubber in the production of asphalt concrete for road pavements built with recycled aggregates consisting of steel slag in relation to possible improvements in structural performance during operation (i.e., fatigue and rutting). Steel slag has a higher bulk specific gravity than natural aggregates, and it has a very porous surface that allows for a different interaction with the bitumen and the crumb rubber compared to traditional aggregates. To this end, two mixtures of asphalt concrete are compared. One was mixed with a modest percentage by weight of crumb rubber using the “dry” technique, and the other mixture did not contain crumb rubber. Indirect tensile and compression tests with cyclic loads were performed to determine the mechanical behaviour of the two mixtures at different temperatures and under different load frequencies. The results of this research indicate the better performance of the modified mixture with crumb rubber, which agrees with other experiments in the literature that have been made using natural aggregates. Furthermore, a significant increase in stiffness was found at high temperatures (up to 30%), a slight reduction (up to 8%) was found at low temperatures, and a reduction in permanent deformation was found under cyclic loads.

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Reduction of the Cement Content by Incorporation of Fine Recycled Aggregates from Construction and Demolition Waste in Rendering Mortars

Infrastructures ◽

10.3390/infrastructures6010011 ◽

2021 ◽

Vol 6 (1) ◽

pp. 11

Author(s):

Sara Jesus ◽

Cinthia Maia Pederneiras ◽

Catarina Brazão Farinha ◽

Jorge de Brito ◽

Rosário Veiga

Keyword(s):

Cement Content ◽

Construction Materials ◽

Recycled Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Concrete Aggregate ◽

Demolition Waste ◽

Construction And Demolition Wastes ◽

Hardened State

The construction sector is responsible for one third of the total wastes produced in the EU. Finding solutions for the reuse or recycling of these wastes is one of the major environmental concerns of modern times. The replacement of sand or cement in specific construction materials, such as concrete or mortars, is a possible solution for these wastes’ management. By using construction and demolition wastes in construction materials, namely on buildings, the cycle of circular economy is closed, increasing the life cycle of the wastes in the same sector. In this research, a reduction of cement content in rendering mortars is analysed. This reduction is achieved by a decrease of the cement/aggregate ratio simultaneously with the incorporation of very fine recycled aggregate from construction and demolition waste. Two recycled aggregates were studied: recycled concrete aggregate (RCA) and mixed recycled aggregate (MRA). The fresh and hardened state properties of the mortars were analysed. Several tests were carried out to evaluate the mortars’ performance, such as mechanical strength tests, water absorption tests, drying tests and shrinkage. It was noticed that the incorporation of RCA led to a better behaviour than in the reference mortar, in terms of mechanical strengths and protection against water.

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Influence of Pozzolan, Slag and Recycled Aggregates on the Mechanical and Durability Properties of Low Cement Concrete

Materials ◽

10.3390/ma14154173 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4173

Author(s):

Eliana Soldado ◽

Ana Antunes ◽

Hugo Costa ◽

Ricardo do do Carmo ◽

Eduardo Júlio

Keyword(s):

Fly Ash ◽

Mechanical Performance ◽

Concrete Surface ◽

Recycled Aggregates ◽

Partial Replacement ◽

Natural Pozzolans ◽

Durability Properties ◽

Chloride Attack ◽

Natural Aggregates ◽

Reduction Of Co2

The sustainability of the construction sector demands the reduction of CO2 emissions. The optimization of the amount of cement in concrete can be achieved either by partially replacing it by additions or by reducing the binder content. The present work aims at optimizing the properties of concrete used in the production of reinforced concrete poles for electrical distribution lines, combining the maximization of compactness with the partial replacement of cement by fly ash, natural pozzolans, and electric furnace slags. Natural aggregates were also partially replaced by recycled ones in mixtures with fly ash. Two types of concrete were studied: a fresh molded one with a dry consistency and a formwork molded one with a plastic consistency. The following properties were characterized: mechanical properties (flexural, tensile splitting, and compressive strengths, as well as Young’s modulus) and durability properties (capillary water absorption, water penetration depth under pressure, resistance to carbonation, chloride migration, and concrete surface resistivity). The service life of structures was estimated, taking the deterioration of reinforcement induced by concrete carbonation or chloride attack into account. Results revealed that mixtures with fly ash exhibit higher mechanical performance and mixtures with fly ash or pozzolans reveal much higher durability results than the full Portland cement-based mixtures.

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