Impact Study on Mechanical Properties of Recycled Concrete Based on Waste Brick Aggregates

Through the experiments of recycling bricks from building waste, the paper studies the mechanical properties and the influence factors of recycled concrete which is based on waste brick aggregates. Using the method of gravels substituted by brick aggregates with the same volume, the optimal mechanical properties can be obtained through adjusting the aggregate contents of different recycled brick sizes, the mix proportion and water consumption of recycled materials. The results of experiments show that there are some key indexes including the bibulous rate of brick aggregates, particle gradations and water consumption, and the optimal size of the brick aggregates ranges from 9.5 mm to 19 mm, and the mechanical properties of recycled concrete are slightly below the referenced concrete by lots of experiments. Therefore, building waste bricks recycled concrete are a kind of very good, sustainable and energy-saving building materials.

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Recycled Concrete Aggregates and Their Influences on Performances of Low and Normal Strength Concretes

Buildings ◽

10.3390/buildings10090167 ◽

2020 ◽

Vol 10 (9) ◽

pp. 167

Author(s):

Mohammed Seddik Meddah ◽

Ali Al-Harthy ◽

Mohamed A. Ismail

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Portland Cement ◽

Recycled Concrete ◽

Construction And Demolition Waste ◽

Recycled Materials ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Natural Aggregates ◽

Normal Strength

Recycled materials are now widely used in various industrial sectors to enhance sustainability and reduce environmental charges. Using recycled aggregates in concrete production significantly lowers demand for natural aggregates and the amount of solid waste sent to landfills. This paper summarizes the main results of a study undertaken to design low and normal strength concrete with various replacement ratios of coarse recycled concrete aggregates (RCA). To persuade the concrete industry to use recycled materials as one of the main components of concrete produced, the overall mechanical and durability performances of the RCA-concrete should be close or even similar to the concrete made with natural ingredients. The present research adopted an approach that consists of designing a series of low and normal strength with RCA having an equal target 28-day design strength to the corresponding natural aggregates concrete but while varying the water–cement ratios (w/c). Coarse recycled concrete aggregates, obtained by crushing waste concrete debris collected from different construction and demolition waste sources, were used in three different proportions of 30%, 50% and 100% (by weight) to produce new concrete with various w/c ratios and different compressive strength grades. Concrete mixes produced with general use Portland cement and various RCA contents were investigated in terms of their key mechanical and durability performances. The mechanical properties (crushing value) of the used RCA were visibly lower than the natural coarse aggregates (NCA). Thus, RCA-concrete showed lower performance than the NCA-concrete. It was found that by using up to 30% coarse RCA, the mechanical properties of concrete were not significantly affected. Beyond 30% of partial replacement of NCA by the coarse RCA, a continuing decrease in the mechanical performance with an increase in RCA amount was found. However, reducing the w/c ratio of concrete designed with the coarse RCA resulted in a compressive strength improvement, a better resistance to sulphate attack, carbonation, and chloride ion penetrations. Additionally, a proper design of Portland cement concrete produced with various proportions of RCA could also contribute to promoting sustainability in the construction industry and lowering its environmental impact.

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Development of new baked bricks based on clay and sawdust

MATEC Web of Conferences ◽

10.1051/matecconf/201814901040 ◽

2018 ◽

Vol 149 ◽

pp. 01040

Author(s):

Omrane Benjeddou ◽

Chokri Soussi ◽

Mohamed Amine Khadimallah ◽

Rayed Alyousef ◽

Malek Jedidi

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Energy Saving ◽

Experimental Work ◽

Manufacturing Process ◽

Building Materials ◽

Physical And Mechanical Properties ◽

Unit Weight ◽

Resistant Material ◽

Cooking Temperature

Current research in the field of building materials is oriented towards the recovery of waste to ensure the lightening of certain building elements and energy saving. The objective of this study is to produce a new bricks by adding sawdust to clay mixtures. The first part of this experimental work consists on detremining the proper manufacturing process and cooking diagram for these new bricks. In the second part, the effect of the maximum cooking temperature, the firing phase time's of the bricks and the sawdust prportion on the physical and mechanical properties of the new bricks have been studied. The studied properties are the absorption ratio, the unit weight and the compressive strength. The results showed that the addition of an increasing amount of sawdust tends to modify the physical and mechanical properties of the cooked samples. The presence of sawdust reduces the number of connections between the clay grains and produces a lighter, more absorbent and less resistant material. Finally, the results showed that the manufacture of bricks based on sawdust is possible.

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Influence of Recycled Materials on Resulting Mechanical Properties of Cement Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.825.53 ◽

2016 ◽

Vol 825 ◽

pp. 53-56

Author(s):

Zdeněk Prošek ◽

Jaroslav Topič ◽

Jan Trejbal ◽

Karel Šeps ◽

Pavel Tesárek

Keyword(s):

Mechanical Properties ◽

High Speed ◽

Resonance Method ◽

Recycled Concrete ◽

Silica Sand ◽

Destructive Testing ◽

Recycled Materials ◽

High Speed Grinding ◽

Marble Powder ◽

Non Destructive

This article presents the mechanical properties of composite materials based on recycled materials which differ in their composition – type of recycled materials. Dynamic modulus of elasticity was monitored during the first 28 days since manufacture by use of non-destructive testing (resonance method). Flexural strength and compressive strength were determined for the 28 days old specimens. The aim of this article was to determine the influence of type and amount of recycled material on the resulting mechanical properties. Mixtures with 3 different microground materials (recycled concrete, marble powder and silica sand) were tested. Microground materials were produced in the company Lavaris (Czech Republic) by use of high speed grinding. The results obtained from these materials were compared with reference material – cement mortar.

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Physical-Mechanical Properties of Cement Composite Building Materials with the Use of Waste of CWB Production

Stroitel nye Materialy ◽

10.31659/0585-430x-2017-749-6-7-9 ◽

2017 ◽

Vol 749 (6) ◽

pp. 7-9

Author(s):

N.V. KUZNETSOVA ◽

◽

O.S. BARINOVA ◽

Keyword(s):

Mechanical Properties ◽

Building Materials ◽

Cement Composite

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Thermal Characterization of Recycled Materials for Building Insulation

Energies ◽

10.3390/en14123564 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3564

Author(s):

Arnas Majumder ◽

Laura Canale ◽

Costantino Carlo Mastino ◽

Antonio Pacitto ◽

Andrea Frattolillo ◽

...

Keyword(s):

Environmental Impact ◽

Environmental Sustainability ◽

Building Materials ◽

Raw Materials ◽

Natural Fibers ◽

Thermal Characterization ◽

Recycled Materials ◽

Building Insulation ◽

Operational Phase

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.

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Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

Materials ◽

10.3390/ma14092323 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2323

Author(s):

Yubing Du ◽

Zhiqing Zhao ◽

Qiang Xiao ◽

Feiting Shi ◽

Jianming Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Size Effect ◽

Compressive Stress ◽

Failure Modes ◽

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Aggregate Concrete ◽

Substitution Ratio ◽

The Impact

To explore the basic mechanical properties and size effects of recycled aggregate concrete (RAC) with different substitution ratios of coarse recycled concrete aggregates (CRCAs) to replace natural coarse aggregates (NCA), the failure modes and mechanical parameters of RAC under different loading conditions including compression, splitting tensile resistance and direct shear were compared and analyzed. The conclusions drawn are as follows: the failure mechanisms of concrete with different substitution ratios of CRCAs are similar; with the increase in substitution ratio, the peak compressive stress and peak tensile stress of RAC decrease gradually, the splitting limit displacement decreases, and the splitting tensile modulus slightly increases; with the increase in the concrete cube’s side length, the peak compressive stress of RAC declines gradually, but the integrity after compression is gradually improved; and the increase in the substitution ratio of the recycled aggregate reduces the impact of the size effect on the peak compressive stress of RAC. Furthermore, an influence equation of the coupling effect of the substitution ratio and size effect on the peak compressive stress of RAC was quantitatively established. The research results are of great significance for the engineering application of RAC and the strength selection of RAC structure design.

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Discrete Element Simulation Analysis of Biaxial Mechanical Properties of Concrete with Large-Size Recycled Aggregate

Sustainability ◽

10.3390/su13137498 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7498

Author(s):

Tan Li ◽

Jianzhuang Xiao

Keyword(s):

Mechanical Properties ◽

Stress State ◽

Strain Curve ◽

Confining Pressure ◽

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Aggregate Model ◽

Large Size

Concrete made with large-size recycled aggregates is a new kind of recycled concrete, where the size of the recycled aggregate used is 25–80 mm, which is generally three times that of conventional aggregate. Thus, its composition and mechanical properties are different from that of conventional recycled concrete and can be applied in large-volume structures. In this study, recycled aggregate generated in two stages with randomly distributed gravels and mortar was used to replace the conventional recycled aggregate model, to observe the internal stress state and cracking of the large-size recycled aggregate. This paper also investigated the mechanical properties, such as the compressive strength, crack morphology, and stress–strain curve, of concrete with large-size recycled aggregates under different confining pressures and recycled aggregate incorporation ratios. Through this research, it was found that when compared with conventional concrete, under the confining pressure, the strength of large-size recycled aggregate concrete did not decrease significantly at the same stress state, moreover, the stiffness was increased. Confining pressure has a significant influence on the strength of large-size recycled aggregate cocrete.

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Roller Compacted Concrete with Recycled Concrete Aggregate for Paving Bases

Sustainability ◽

10.3390/su12083154 ◽

2020 ◽

Vol 12 (8) ◽

pp. 3154 ◽

Cited By ~ 2

Author(s):

Hedelvan Emerson Fardin ◽

Adriana Goulart dos Santos

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Modulus Of Elasticity ◽

Splitting Tensile Strength ◽

Recycled Concrete ◽

Concrete Aggregate ◽

Recycled Concrete Aggregate ◽

Roller Compacted Concrete ◽

Flexural Tensile Strength ◽

Mechanical And Physical Properties

This research aimed to investigate the mechanical and physical properties of Roller Compacted Concrete (RCC) used with Recycled Concrete Aggregate (RCA) as a replacement for natural coarse aggregate. The maximum dry density method was adopted to prepare RCC mixtures with 200 kg/m³ of cement content and coarse natural aggregates in the concrete mixture. Four RCC mixtures were produced from different RCA incorporation ratios (0%, 5%, 15%, and 30%). The compaction test, compressive strength, splitting tensile strength, flexural tensile strength, and modulus of elasticity, porosity, density, and water absorption tests were performed to analyze the mechanical and physical properties of the mixtures. One-way Analysis of Variance (ANOVA) was used to identify the influences of RCA on RCC’s mechanical properties. As RCA increased in mixtures, some mechanical properties were observed to decrease, such as modulus of elasticity, but the same was not observed in the splitting tensile strength. All RCCs displayed compressive strength greater than 15.0 MPa at 28 days, splitting tensile strength above 1.9 MPa, flexural tensile strength above 2.9 MPa, and modulus of elasticity above 19.0 GPa. According to Brazilian standards, the RCA added to RCC could be used for base layers.

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C80 Early Strength Micro Expansion of Steel Tube Reinforced Concrete Research

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1119.752 ◽

2015 ◽

Vol 1119 ◽

pp. 752-755

Author(s):

Chang Zheng Sun ◽

Zheng Wang

Keyword(s):

High Performance ◽

Raw Materials ◽

Influence Factors ◽

High Strength ◽

Steel Tube ◽

Strength Analysis ◽

Self Compacting Concrete ◽

Mix Proportion ◽

Early Strength ◽

Working Performance

Optimization of mix proportion parameter ，Using ordinary raw materials makes a C80 high performance self-compacting concrete;By joining a homemade perceptual expansion agent, significantly improve the early strength of concrete and effective to solve the high strength of self-compacting concrete caused by gelled material consumption big contraction;Further study on the working performance of high-strength self-compacting concrete, age strength, analysis the influence factors of concrete are discussed.

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