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 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 Strength and Water Absorption of Sustainable Concrete Produced with Recycled Basaltic Concrete Aggregates and Powder

2021 ◽  
Vol 13 (11) ◽  
pp. 6277
Author(s):  
Ibrahim Sharaky ◽  
Usama Issa ◽  
Mamdooh Alwetaishi ◽  
Ahmed Abdelhafiz ◽  
Amal Shamseldin ◽  
...  
Keyword(s):  
Water Absorption ◽  
Edge Length ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Substitution ◽  
Small Reduction ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Sustainable Concrete

In this study, the recycled concrete aggregates and powder (RCA and RCP) prepared from basaltic concrete waste were used to replace the natural aggregate (NA) and cement, respectively. The NA (coarse and fine) was replaced by the recycled aggregates with five percentages (0%, 20%, 40%, 60% and 80%). Consequently, the cement was replaced by the RCP with four percentages (0%, 5%, 10% and 20%). Cubes with 100 mm edge length were prepared for all tests. The compressive and tensile strengths (fcu and ftu) and water absorption (WA) were investigated for all mixes at different ages. Partial substitution of NA with recycled aggregate reduced the compressive strength with different percentages depending on the type and source of recycled aggregate. After 28 days, the maximum reduction in fcu value was 9.8% and 9.4% for mixtures with coarse RCA and fine RCA (FRCA), respectively. After 56 days, the mixes with 40% FRCA reached almost the same fcu value as the control mix (M0, 99.5%). Consequently, the compressive strengths of the mixes with 10% RCA at 28 and 56 days were 99.3 and 95.2%, respectively, compared to those of M0. The mixes integrated FRCA and RCP showed higher tensile strengths than the M0 at 56 d with a very small reduction at 28 d (max = 3.4%). Moreover, the fcu and ftu values increased for the late test ages, while the WA decreased.

scholarly journals Los Angeles index and water absorption capacity of crushed aggregates

2020 ◽  
Vol 15 (1) ◽  
pp. 65-78
Author(s):  
Mohammed Abed ◽  
Rita Nemes
Keyword(s):  
Los Angeles ◽  
Water Absorption ◽  
High Performance Concrete ◽  
Absorption Capacity ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Aggregate Concrete ◽  
Crushed Aggregate

Abstract The mechanical and physical properties of the crushed aggregate have been studied. The properties of crushed aggregate, which produced from recycled aggregate concrete is not discussed in the literature yet despite it could be a choice in some circumstances like in case of demolishing the structures that already constructed by recycled aggregate concrete. Twenty-two types of self-compacting high-performance concrete made by coarse natural aggregate and coarse recycle concrete aggregate have been crushed and their properties have been studied. The main findings of the present study that, the Los Angeles index and water absorption of crushed aggregate is affected by the coarse recycled concrete aggregate dosage in its parent concrete, as well as, incorporating cement replacing materials in parent concrete help to enhance the abrasion resistance of crushed aggregate.

scholarly journals Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
C. Varrone ◽  
T. M. B. Heggeset ◽  
S. B. Le ◽  
T. Haugen ◽  
S. Markussen ◽  
...  
Keyword(s):  
Crude Glycerol ◽  
Degradation Efficiency ◽  
Anaerobic Sludge ◽  
Growth Media ◽  
Fed Batch ◽  
Microbial Composition ◽  
Fermentation Products ◽  
Substrate Degradation ◽  
Microbial Cultures ◽  
Mixed Microbial Cultures

Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such asClostridium,Klebsiella, andEscherichia.

scholarly journals Impact of the Content Variation of the Different Recycled Wastes to the Properties of Concrete Paving Block

2018 ◽  
Vol 206 ◽  
pp. 02004 ◽  
Author(s):  
X Wang ◽  
C S Chin ◽  
J Xia
Keyword(s):  
Water Absorption ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Coarse Aggregates ◽  
Content Variation ◽  
The Impact

Recycled concrete aggregates have been widely studied and used in concrete products nowadays. However, other recycled wastes, such as glass, have not been involved too much in recycled aggregate concrete studies. This paper aims to study the impact of the content variation of the different recycled wastes to the properties of the concrete paving block. In this paper, not only recycled coarse concrete aggregates, crushed glass are also used as the recycled aggregate in the concrete paving block in different replacement levels. According to test the properties of blocks mixed with different recycled wastes, the experimental results indicate that: (1) adding recycled concrete coarse aggregate (RCCA) in the blocks can decrease the blocks’ strength, and increase the water absorption. The suggested replacement levels for RCCA is 60%; (2) mixing crushed glass (CG) in the concrete paving blocks as a type of coarse aggregates can obviously improve the blocks’ strength and decrease the blocks’ water absorption.

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 Recycled Precast Concrete Kerbs and Paving Blocks, a Technically Viable Option for Footways

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7007
Author(s):  
Andrés Juan-Valdés ◽  
Desirée Rodríguez-Robles ◽  
Julia García-González ◽  
María Isabel Sánchez de Rojas ◽  
Manuel Ignacio Guerra-Romero ◽  
...  
Keyword(s):  
Water Absorption ◽  
Circular Economy ◽  
Precast Concrete ◽  
Research Work ◽  
Lower Class ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Durability ◽  
Conventional Concrete

The linear economy paradigm in place to date has to be seriously challenged to give way to a new school of thought known as the circular economy. In this research work, precast kerbs and paving blocks made with recycled concrete (RACC-mixture) bearing 50 wt% mixed recycled aggregate (masonry content of 33%) and an eco-efficient cementitious material as 25 wt% conventional binder replacement were evaluated to assess their intrinsic potential to replace traditional raw materials, in keeping with circular economy criteria. Therefore, precast products were subjected to mechanical strength, durability and microstructure tests and were compared to conventional concrete units (CC-mixture and commercially available precast elements). Although a class demotion was observed for water absorption and some decreases in flexural strength (26%), splitting tensile strength (12.8%) and electrical resistivity (45%) and a lower class water absorption were registered, and the recycled mixture also exhibited a greater performance in terms of compressive strength (6%), a better abrasion resistance classification and a comparable porosity and microstructure, which ensures a good concrete durability. In any case, the results showed that precast pieces were European standard-compliant, thus supporting the viability of the mixed recycled aggregates and eco-efficient cementitious replacement in footways.

scholarly journals Evaluating the durability of recycled concrete made of coarse recycled aggregate concrete containing silica-fume and natural zeolite

2020 ◽  
Vol 19 (3) ◽  
pp. 457-473
Author(s):  
Hasan Jalilifar ◽  
◽  
Fathollah Sajedi ◽  
Vahid Razavi Toosi ◽  
◽  
...  
Keyword(s):  
Water Absorption ◽  
Silica Fume ◽  
Natural Zeolite ◽  
Full Scale ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Conventional Concrete ◽  
Aggregate Concrete ◽  
Four Levels

This experimental study evaluates the durability of recycled aggregate concrete (RAC) containing silica-fume (SF) and natural zeolite (NZ). For this purpose, four levels of recycled coarse concrete aggregates (RCA) were replaced with natural coarse aggregates (NCA). To compare the effect of pozzolans, three levels of SF (5%, 10%, and 15%) and three levels of NZ (10%, 20%, and 30%) were replaced with cement. To evaluate the durability of RAC, 28 mixed designs were made and the following were measured: compressive strength (CS), water absorption by immersion (WA by immersion), water absorption by capillary (WA by capillary), electrical resistance (ER), electrical conductivity (EC) and rapid chloride penetration test (RCPT). The results indicated that WA by immersion and WA by capillary of RAC increased with enhanced RCA incorporation. On the other hand, the pozzolanic reaction of 10% of SF and 10% of NZ decreased capillary pores and structural weakness of full-scale RAC. However, due to the internal chemical changes of RAC, contrary to the WA by immersion and WA by capillary, compared to conventional concrete (CC), a lower EC and unchanged ER values of RC100 containing pozzolans were seen. The scanning electron microscopy (SEM) revealed that compared to NZ, a 10% of SF significantly improved the microstructure of full scale RAC.

Influence of Water Repellent Surface Impregnation on Water Absorption Properties of Recycled Aggregate Concrete

2011 ◽  
Vol 71-78 ◽  
pp. 5011-5014 ◽  
Author(s):  
Ya Guang Zhu ◽  
Pei Zhen Xu ◽  
Qiu Yi Li ◽  
Chuan Li
Keyword(s):  
Surface Water ◽  
Water Absorption ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Water Repellent ◽  
Capillary Water ◽  
Absorption Properties ◽  
Aggregate Concrete ◽  
Capillary Water Absorption

This paper aimed to investigate the influence of using silane surface water repellent treatment on the capillary water absorption properties of recycled aggregate concrete. In this study, two types of coarse aggregate, natural aggregates and recycled aggregates were used, and the surface water repellent treatment of concrete was produced by brushing 100g/m2 and 200g/m2 of paste. It was found that the silane impregnation depth of recycled concrete was deeper than that of natural concrete, and the surface treatment was more effective in the improvement of capillary water absorption properties of recycled aggregate concrete than the natural aggregate concrete.

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