Efficiency of Bio-Sourced Composites in Confining Recycled Aggregates Concrete

2022 ◽  
Author(s):  
Elhem Ghorbel ◽  
Mariem Limaiem
Keyword(s):  
Mechanical Behavior ◽  
Analytical Modeling ◽  
Mechanical Characteristics ◽  
Epoxy Polymer ◽  
Experimental Results ◽  
Confined Concrete ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Traditional System ◽  
Flax Fibers

This research investigates the efficiency of using Flax Fibers reinforced bio-sourced polymer by comparison to traditional system based on Carbone Fiber Reinforced Epoxy Polymer in order to confine recycled aggregates concrete. Four concrete formulations have been formulated by incorporating recycled aggregates from demolition waste (0%, 30%, 50% and 100%). An air-entraining agent was added to the formulations to achieve the level of 4% occluded air. The main objective is to discuss and to evaluate the effectiveness of confining them using bio-sourced composite by comparison to traditional ones. To hit this target, the developed approaches are both experimental and analytical. The first part is experimental and aimed to characterize the mechanical behavior of the materials: the composites used in the confining process the unconfined concrete (effect of incorporating recycled aggregates on the overall mechanical characteristics). We establish that bio-sourced composites are efficient in strengthening recycled aggregates concrete especially if they are air-entrained. The second part of this work is dedicated to analytical modeling of mechanical behavior of confined concrete with composite under compression based on Mander’s model. The input parameters of the model were modified to consider the rate of recycled aggregates incorporation. Comparison between experimental results and the modified Mandel’s Model is satisfactory.

scholarly journals Tests and Simulation of the Bond-Slip between Steel and Concrete with Recycled Aggregates from CDW

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 40
Author(s):  
Miguel Bravo ◽  
António P. C. Duarte ◽  
Jorge de Brito ◽  
Luís Evangelista
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Experimental Results ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Bond Slip ◽  
Model Code ◽  
Pull Out ◽  
Natural Aggregates

This works intends to analyze, experimentally and numerically, the bond-slip behavior between steel and concrete made with recycled aggregates (RA) from construction and demolition waste (CDW) from several recycling plants in Portugal. Pull-out tests performed in concrete mixes with RA from CDW are described and the main results (bond strength, bond-slip curves and failure modes) are shown and discussed. Additionally, a comparison between experimental and analytical (using equations from the literature) results is made. Afterwards, finite element (FE) models using Abaqus are developed and compared with the experimental results. The interface behavior between steel and concrete follows that prescribed by the CEB-FIP Model Code and uses as input experimental results. After validation, the models show good results when extended to predict the bond-slip behavior of the remaining concrete mixes studied. It is generally concluded that, per each 10% of natural aggregates replaced with RA from CDW, the bond strength decreases in circa 3% (numerically) to 5% (experimentally). CEB-FIP Model Code equations are shown to be able to predict bond strength and, when used in FE models, to lead to accurate simulation of the bond-slip response of steel and concrete with RA from CDW: the average ratio between numerical and experimental bond strengths is 0.95. In the scope of the FE models developed, a simple equation to be used along with those prescribed by CEB-FIP, which accounts for fraction and ratio of aggregates replaced, is put forward, as a first approach, showing good results.

Cementitious Composites Using Recycled Waste

2015 ◽  
Vol 754-755 ◽  
pp. 833-837 ◽  
Author(s):  
Attila Puskás ◽  
Ofelia Corbu ◽  
Andrei Victor Sandhu ◽  
Mohd Mustafa Al Bakri Abdullah
Keyword(s):  
European Union ◽  
Textile Industry ◽  
Management Practices ◽  
Mechanical Characteristics ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Cementitious Composites ◽  
Economic Downturn ◽  
Demolition Waste ◽  
Recycled Waste

European Union faces challenge in the waste management practices. Despite the economic downturn and the decrease in consumption at European Union level the waste generation stays stable, and the recycling disposal stagnates. Since the level of the recycling and recovery is set at 70% for the year 2020 for the construction and demolition waste for achieving the proposed level practical possibilities for recycling of large quantities are necessary. The paper presents cementitious composites using recycled waste which might represent practical solution for increasing the rate of recycling of construction and demolition waste and of textile industry waste. Mechanical characteristics of two different composites using recycled wastes are presented. The first cementitious composition incorporates recycled aggregates substituting new, non-renewable natural aggregates, while the second composition – beside the recycled aggregates – contains also textile industrial waste. The mechanical characteristics of the obtained compositions are comparable with the ones of the road concrete, in the same time fulfilling also the norm requirements for composites used for road concrete. The proposed cementitious composites represent significant potential for recycling, and as consequence, potential for achieving the targeted rate of the recycling.

scholarly journals Mechanical behavior of recycled lightweight concrete using EVA waste and CDW under moderate temperature

2009 ◽  
Vol 2 (3) ◽  
pp. 211-221 ◽  
Author(s):  
E. Q. R. Santiago ◽  
P. R. L. Lima ◽  
M. B. Leite ◽  
R. D. Toledo Filho
Keyword(s):  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Lightweight Concrete ◽  
Recycled Concrete ◽  
Raw Material ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Experimental Program ◽  
Demolition Waste

Many benefits can be achieved by using recycled waste as raw material for construction. Some of them are the reduction of the total cost of the construction, the reduction of the consumption of energy and the decrease in the use of natural materials. The construction sector can also incorporate the waste of the other industries, like the waste of the shoes industry, the Ethylene Vinyl Acetate (EVA). EVA aggregate is obtained by cutting off the waste of EVA expanded sheets used to produce insoles and innersoles of the shoes. In this work two types of recycled aggregate were used - construction and demolition waste (CDW) and EVA. The aim of this work was to study the influence of the use of these recycled aggregates, as replacement of the natural coarse aggregate, on mechanical behavior of recycled concrete. The experimental program was developed with two w/c ratio: 0.49 and 0.82. Four mixtures with produced with different aggregates substitution rates (0, 50%EVA, 50%CDW and 25%EVA-25%CDW), by volume. Compressive tests were carried out to evaluable the influence of recycled aggregate on strength, elastic modulus and Poisson coefficient. In addition, it was evaluated the effect of the moderate temperatures (50, 70 and 100º C) on stress-strain behavior of concretes studied. The results demonstrated that is possible to use the EVA waste and RCD to produces lightweight concrete. The influence of temperature was more significant only on elastic modulus of the recycled concrete with 50%EVA.

scholarly journals Analytical Modeling of the Mechanical Behavior of MEMS/NEMS-Multilayered Resonators with Variable Cross-Sections for Sensors and Energy Harvesters

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Eustaquio Martinez-Cisneros ◽  
Luis A. Velosa-Moncada ◽  
Ernesto A. Elvira-Hernandez ◽  
Omar I. Nava-Galindo ◽  
Luz Antonio Aguilera-Cortes ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Cross Sections ◽  
Analytical Modeling ◽  
Variable Cross ◽  
Energy Harvesters

scholarly journals Application of Construction and Demolition Waste in Civil Construction in the Brazilian Amazon—Case Study of the City of Rio Branco

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2247
Author(s):  
Fernando da Silva Souza ◽  
José Maria Franco de Carvalho ◽  
Gabriela Grotti Silveira ◽  
Vitória Cordeiro Araújo ◽  
Ricardo André Fiorotti Peixoto
Keyword(s):  
Mechanical Strength ◽  
Raw Materials ◽  
Amazon Region ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Federal State ◽  
Construction Sites ◽  
Demolition Waste ◽  
Conventional Concrete ◽  
Initial Adhesion

The lack of usable aggregates for civil construction in Rio Branco (capital of Acre, a Federal State in the Amazon region) makes the production and use of recycled aggregates from construction and demolition waste (CDW) an alternative of great interest. In this study, a comprehensive characterization of CDW collected from 24 construction sites of six building types and three different construction phases (structures, masonry, and finishing) was carried out. The fine and coarse recycled aggregates were produced and evaluated in 10 different compositions. The aggregates’ performance was evaluated in four mixtures designed for laying and coating mortars with a total replacement of conventional aggregates and a mixture designed for a C25 concrete with 50% and 100% replacement of conventional aggregates. CDW mortars showed lower densities and greater water retention, initial adhesion, and mechanical strength than conventional mortars. CDW concretes presented lower densities and greater resistance to chloride penetration than conventional concrete, with a small mechanical strength reduction. The recycled CDW aggregates proved to be technologically feasible for safe application in mortars and concrete; for this reason, it is believed that the alternative and proposed methodology is of great interest to the Amazonian construction industry, considering the high costs of raw materials and the need for defining and consolidating a sustainable development model for the Amazon region.

Mechanical behavior of PVC tube confined concrete and PVC-FRP confined concrete: A review

Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 613-635
Author(s):  
Chaochao Feng ◽  
Feng Yu ◽  
Yuan Fang
Keyword(s):  
Mechanical Behavior ◽  
Confined Concrete

Mechanical Behavior for some Cobalt Alloys

2015 ◽  
Vol 1114 ◽  
pp. 9-12
Author(s):  
Alexandru Ghiban ◽  
Brandusa Ghiban ◽  
Cristina Maria Borţun ◽  
Nicolae Serban ◽  
Mihai Buzatu
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Mechanical Behavior ◽  
Mechanical Characteristics ◽  
Fractographic Analysis ◽  
Cobalt Alloys ◽  
Dental Alloys ◽  
Bending Tests ◽  
Longitudinal Modulus

Four compositions of some usually commercial dental alloys were investigated in order to determine the mechanical characteristics and fractographic analysis of tensile and bending tests surfaces. A correlation between chemical composition (either molybdenum or molybdenum and chromium contents) and mechanical characteristics (longitudinal modulus, tensile strength and elongation) were finally done.

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