scholarly journals Use of Mixed Microbial Cultures to Protect Recycled Concrete Surfaces: A Preliminary Study

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6545
Author(s):  
Lorena Serrano-González ◽  
Daniel Merino-Maldonado ◽  
Manuel Ignacio Guerra-Romero ◽  
Julia María Morán-Del Pozo ◽  
Paulo Costa Lemos ◽  
...  
Keyword(s):  
Water Drop ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Durability ◽  
Demolition Waste ◽  
Microbial Cultures ◽  
Bio Oil ◽  
Preliminary Study ◽  
Mixed Microbial Cultures

One approach to tackle the problems created by the vast amounts of construction and demolition waste (CDW) generated worldwide while at the same time lengthening concrete durability and service life is to foster the use of recycled aggregate (RA) rather than natural aggregate (NA). This article discusses the use of polyhydroxyalkanoates (PHAs)-producing mixed microbial cultures (MMCs) to treat the surface of recycled concrete with a view to increase its resistance to water-mediated deterioration. The microorganisms were cultured in a minimal medium using waste pinewood bio-oil as a carbon source. Post-application variations in substrate permeability were determined with the water drop absorption and penetration by water under pressure tests. The significant reduction in water absorption recorded reveals that this bioproduct is a promising surface treatment for recycled concrete.

scholarly journals Use of Bioproducts Derived from Mixed Microbial Cultures Grown with Crude Glycerol to Protect Recycled Concrete Surfaces

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2057
Author(s):  
Lorena Serrano-González ◽  
Daniel Merino-Maldonado ◽  
Manuel Ignacio Guerra-Romero ◽  
Julia María Morán-del Pozo ◽  
Paulo Costa Lemos ◽  
...  
Keyword(s):  
Water Absorption ◽  
Crude Glycerol ◽  
Protective Layer ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
World Population ◽  
Management Problem ◽  
Waste Glycerol ◽  
Microbial Cultures ◽  
Mixed Microbial Cultures

The large increase in the world population has resulted in a very large amount of construction waste, as well as a large amount of waste glycerol from transesterification reactions of acyl glycerides from oils and fats, in particular from the production of biodiesel. Only a limited percentage of these two residues are recycled, which generates a large management problem worldwide. For that reason, in this study, we used crude glycerol as a carbon source to cultivate polyhydroxyalkanoates (PHA)-producing mixed microbial cultures (MMC). Two bioproducts derived from these cultures were applied on the surface of concrete with recycled aggregate to create a protective layer. To evaluate the effect of the treatments, tests of water absorption by capillarity and under low pressure with Karsten tubes were performed. Furthermore, SEM-EDS analysis showed the physical barrier caused by biotreatments that produced a reduction on capillarity water absorption of up to 20% and improved the impermeability of recycled concrete against the penetration of water under pressure up to 2.7 times relative to the reference. Therefore, this bioproduct shown to be a promising treatment to protect against penetration of water to concrete surfaces increasing its durability and useful life.

scholarly journals Influence of Partial Coarse Fraction Substitution of Natural Aggregate by Recycled Concrete Aggregate in Hot Asphalt Mixtures

2019 ◽  
Vol 12 (1) ◽  
pp. 250 ◽  
Author(s):  
Debora Acosta Álvarez ◽  
Anadelys Alonso Aenlle ◽  
Antonio José Tenza-Abril ◽  
Salvador Ivorra
Keyword(s):  
Asphalt Concrete ◽  
Coarse Fraction ◽  
Asphalt Mixtures ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Demolition Waste ◽  
Natural Aggregate

The main objective of this work is to evaluate the properties of hot asphalt mixtures that have been manufactured with different recycled concrete aggregate (RCA) percentages (0%, 20%, 40%, 60% and 80% of the fraction 5–13 mm) and asphalt (4%, 4.5% and 5%). Dense asphalt mixtures were made; partially replacing the natural aggregate (NA) fraction between 5 and 13 mm. Marshall specimens were manufactured to determine the main properties of the asphalt concrete (AC) in terms of density, voids, stability and deformation. Additionally, the optimal asphalt content (OAC) was determined, and measured the water sensibility, the stiffness modulus and the permanent deformation. The results corroborate the potential for using these sources of construction and demolition waste (CDW) as a RCA in asphalt concrete and show that the hot asphalt mixtures with up to 40% substitution of natural aggregate by recycled aggregate in the fraction 5–13 mm present good behavior.

A Brief Analysis of Domestic Construction and Demolition Waste Recycling Techniques

2012 ◽  
Vol 509 ◽  
pp. 1-5
Author(s):  
Su Ping Cui ◽  
Qi Dong Liu ◽  
Jian Hua Yan ◽  
Xin Du
Keyword(s):  
Natural Disaster ◽  
Waste Recycling ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Demolition Waste ◽  
Construction Waste ◽  
Healthy Development ◽  
Industrial Chain ◽  
Recycling Techniques

In this paper, the construction and demolition waste (C&D waste) recycling techniques in China is summarized, and proposed the C&D waste recycling suggestions in this foundation. The C&D waste can be divided into construction waste, decorating waste, demolition waste and natural disaster ruin waste. In addition to be buried, domestic C&D waste can be made into landscape material, roadbed material, recycled aggregate, recycled brick, recycled concrete, recycled admixture and so on. The state should establish positive promoting policies, improve the recycling industrial chain, and promote the healthy development of the C&D waste recycling.

scholarly journals Recycled concrete with coarse recycled aggregate. An overview and analysis

2018 ◽  
Vol 68 (330) ◽  
pp. 151 ◽  
Author(s):  
B. González-Fonteboa ◽  
S. Seara-Paz ◽  
J. De Brito ◽  
I. González-Taboada ◽  
F. Martínez-Abella ◽  
...  
Keyword(s):  
Natural Resources ◽  
State Of The Art ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Relevant Research ◽  
Demolition Waste ◽  
Waste Storage ◽  
Concrete Properties ◽  
Creep And Shrinkage

The construction field has contributed to environmental degradation, producing a high amount of construction and demolition waste (C&D waste) and consuming large volumes of natural resources. In this context, recycled concrete (RC) has been recognised as a means to preserve natural resources and reduce space for waste storage. During the last decades, many researchers have developed works studying different recycled concrete properties. This review focuses on structural RC made with coarse recycled aggregate from concrete waste. The main objective is to provide a state of the art report on RC’s properties and an analysis on how to predict them taking into account relevant research works. Moreover, the study tries to collect and update RC findings, proposing equations to define RC’s performance, in terms of mechanical strength, modulus of elasticity, stress-strain, creep and shrinkage.

scholarly journals Bond Behavior Between Recycled Concrete Containing CDW and Different Types of Steel Bars

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Carine N. S. Reis ◽  
Paulo R. L. Lima ◽  
Mônica B. Leite
Keyword(s):  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Conventional Concrete ◽  
Recycled Fine Aggregate ◽  
Steel Bar ◽  
Internal Forces ◽  
Steel Rebars

The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete, which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements. The modification of the concrete composition, with the introduction of recycled aggregate from construction and demolition waste (CDW), affects the steel-concrete interface and can modify the bonding stress, which is also influenced by the type and diameter of the bar used. In this work, the influence of the recycled fine aggregate (RFA) and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test. Conventional concrete and recycled concrete, with RFA replacement level of 25%, were produced. Two types of steel rebars (i.e.,plain and deformed) with  diameters of 10.0 and 16.0mm were considered in this paper. The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate, but this trend is influenced by the diameter of the bar used. The use of ribbed bars modifies the stress bon-slip behavior, with an increase in the average bond strength, which is also observed with the reduction of the diameter of the bar.

Estimation of Water Absorption Capacity of Hardened Concrete with Recycled Aggregate Based on Experimental Determination

2015 ◽  
Vol 732 ◽  
pp. 411-414 ◽  
Author(s):  
Tereza Pavlů ◽  
Magdaléna Šefflová
Keyword(s):  
Water Absorption ◽  
Negative Impact ◽  
High Water ◽  
Absorption Capacity ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Hardened Concrete ◽  
Water Absorption Capacity ◽  
Demolition Waste

Recycled construction and demolition waste, especially recycled concrete, is able to use as an aggregate for concrete. The high water absorption capacity (WA) of recycled aggregate has a negative impact of concrete mix workability and influences the water-cement ratio. This paper presents results of experimental measurement of WA of recycled aggregate and recycled concrete. Series of concrete samples with various replacement ratios of natural aggregate and recycled aggregate were prepared for this study. The main aim of this study is to analyze the influence of recycled aggregate WA, and mixture ratios on the WA of hardened concrete (HC). Regression model to estimate the WA of hardened concrete is presented.

scholarly journals Development of Concrete Incorporating Recycled Aggregates, Hydrated Lime and Natural Volcanic Pozzolan

2021 ◽  
Vol 6 (11) ◽  
pp. 155
Author(s):  
Natividad Garcia-Troncoso ◽  
Bowen Xu ◽  
Wilhenn Probst-Pesantez
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Demolition Waste ◽  
Crushed Concrete ◽  
Natural Pozzolana ◽  
Concrete Materials

Recycling of construction and demolition waste is a central point of discussion throughout the world. The application of recycled concrete as partial replacement of mineral aggregates in concrete mixes is one of the alternatives in the reduction of pollution and savings in carbon emissions. The combined influence of the recycled crushed concrete, lime, and natural pozzolana on the mechanical and sustainable properties of concrete materials is firstly proposed in this study. In this research, unconventional construction materials are employed to produce concrete: the recycled crushed concrete is used as coarse aggregate, while lime and natural pozzolana are used as a partial replacement for cement. Substitutions of 10%, 20%, 50% of gravel are made with recycled aggregates, and 2%, 5%, 10% of cement with lime and natural pozzolan. Tests on the fresh and hardened properties, destructive (compressive strength) and non-destructive tests (sclerometer rebound and ultrasound) of mixtures are carried out. It is shown that the use of recycled materials can provide an increase in compressive strength of up to 34% with respect to conventional concrete. Life cycle cost and sustainability assessments indicate that concrete materials incorporating recycled aggregate possess good economic and environmental impacts.

scholarly journals PROPERTIES OF RECYCLED AGGREGATE CONCRETE

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mirjana Malešev ◽  
Vlastimir Radonjanin ◽  
Gordana Broćeta
Keyword(s):  
Great Powers ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Recycling Industry ◽  
Concrete Mixtures

Following an example of the world's great powers that developed the recycling industry after natural disasters and wars, the paper points to the possibility of using large quantities of construction and demolition waste, generated as a result of the recent floods in the BiH and Serbia. Based on the years of extensive experimental research, and the research conducted by eminent experts, an overview is provided of the most basic properties and application of recycled aggregate concrete. It has been shown that the application of coarse recycled concrete aggregate, as the component materials in the concrete mixtures, it is possible to produce structural concrete that can be satisfactory and even with high quality, which primarily depends on the characteristics of crushed demolished concrete.

A Novel Conceptual Approach for Predicting the Mechanical Properties of Recycled Aggregate Concrete

2016 ◽  
Vol 847 ◽  
pp. 156-165
Author(s):  
Marco Pepe ◽  
Eduardus Koenders ◽  
Romildo Dias Toledo Filho ◽  
Enzo Martinelli
Keyword(s):  
Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Conceptual Approach ◽  
Demolition Waste ◽  
Predictive Capacity ◽  
Moisture Condition

The construction sector is more and more committed to reduce its environmental impacts. One of the key actions undertaken in the last decade deals with the ability of turning construction and demolition waste into new raw materials. For instance, the use of recycled aggregates for producing new concrete was one of the most investigated. Thus, in the last decade, plenty of researches were involved in project on characterising the mechanical behaviour of concrete made with recycled aggregates. However, these projects were mainly experimental in nature and generally led to merely empirical formulations. Conversely, this paper is intended at providing a contribution for predicting the mechanical properties of Recycled Aggregates Concrete (RAC). Particularly, it aims at quantifying the effect of replacing ordinary aggregates with Recycled Concrete Aggregates (RCA) on the resulting compressive strength of RAC. To this end, a conceptual model considering both the relevant physical properties of regular and recycled aggregates, including the attached mortar content, and the hydration reactions of Portland cement paste is proposed. The actual predictive capacity of the proposed model is assessed through an experimental validation against experimental tests carried out on several concrete batches produced with various values for the different keys parameters, such as the nominal water-to-cement ratio, the aggregates replacement ratio and the initial moisture condition of aggregates. Both the experimental data and the theoretical formulations proposed in this paper stem out from the inter-university collaboration developed as part of the EU funded EnCoRe Project (www.encore-fp7.unisa.it).

scholarly journals Influence of Wetting and Drying Cycles on Physical and Mechanical Behavior of Recycled Aggregate Concrete

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5675
Author(s):  
Caroline S. Rangel ◽  
Mayara Amario ◽  
Marco Pepe ◽  
Enzo Martinelli ◽  
Romildo D. Toledo Filho
Keyword(s):  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Wetting And Drying ◽  
Aggregate Concrete ◽  
Wetting And Drying Cycles ◽  
The Impact

Recently, concerns have been rising about the impact of increasing the depletion of natural resources and the relevant generation of construction and demolition waste, on the environment and economy. Therefore, several efforts have been made to promote sustainable efficiency in the construction industry and the use of recycled aggregates derived from concrete debris for new concrete mixtures (leading to so-called recycled aggregate concrete, RAC) is one of the most promising solutions. Unfortunately, there are still gaps in knowledge regarding the durability performances of RAC. In this study, we investigate durability of structural RAC subjected to wet-dry cycles. We analyze the results of an experimental campaign aimed at evaluating the degradation process induced by wetting and drying cycles on the key physical and mechanical properties of normal- and high-strength concrete, produced with coarse recycled concrete aggregates (RCAs) of different sizes and origins. On the basis of the results we propose a degradation law for wetting and drying cycles, which explicitly makes a possible correlation between the initial concrete porosity, directly related to the specific properties of the RCAs and the resulting level of damage obtained in RAC samples.

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