scholarly journals Properties and Microstructure Distribution of High-Performance Thermal Insulation Concrete

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2091 ◽  
Author(s):  
Malek Mohammad ◽  
Eyad Masad ◽  
Thomas Seers ◽  
Sami G. Al-Ghamdi
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
High Performance ◽  
Lightweight Concrete ◽  
Concrete Mixture ◽  
Unit Weight ◽  
Expanded Perlite ◽  
Micro Computed Tomography ◽  
Structural Applications

The aim of this experimental study is to develop high strength and lightweight concrete mixture suitable for structural applications. This work investigates the effect of replacing normal aggregate either partially or totally with expanded perlite aggregate. This material allows for better thermal insulation properties, thus decreasing the energy usage within the life cycle of the concrete structure. Expanded perlite aggregate was used in concrete by 20%, 40%, 60%, 80%, and 100% in replacement of the natural aggregate. Material characterization tests of compressive strength, flexural strength, and thermal conductivity were carried out for six concrete mixtures. In addition, microstructure analysis was performed with the aid of a micro-computed tomography system to investigate the effects and relation of microstructure quantities on material properties. The proposed concrete mixture, which has 100% of expanded perlite aggregate, has a unit weight of 1703 kg/m3 and achieved reduction percentage of thermal conductivity around 62% (1.81 to 0.69 W·m−1·K−1) and a compressive strength of 42 MPa at 28 days; and thus is ideal for structural applications with enhanced properties.

scholarly journals Durability of Structural Lightweight Concrete Containing Expanded Perlite Aggregate

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Mohammed Ibrahim ◽  
Aftab Ahmad ◽  
Mohammed S. Barry ◽  
Luai M. Alhems ◽  
A. C. Mohamed Suhoothi
Keyword(s):  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Seismic Loading ◽  
Normal Weight ◽  
Chloride Diffusion ◽  
Unit Weight ◽  
Reinforcing Steel ◽  
Expanded Perlite ◽  
Chloride Permeability

Abstract This study focuses on the development of durable structural lightweight concrete (LWC) by incorporating expanded perlite aggregate (EPA) in the range of 0 to 20% by weight. In order to ensure its durability when exposed to chloride environment, concrete was produced with low water-to-cement ratio and ordinary Portland cement (OPC) was replaced with 50% and 7% ground granulated blast furnace slag (GGBFS) and silica fume (SF), respectively. The mechanical properties and durability of concrete were assessed by determining the unit weight, compressive strength, flexural strength, drying shrinkage, chloride permeability and migration, as well as resistance of concrete to corrosion of reinforcing steel. Very importantly, thermal insulation properties were determined using a hot guarded plate. In addition, a finite element model (FEM) was prepared to study the behavior of EPA-modified concrete under seismic loading. The results showed that the unit weight of concrete was reduced by 20% to 30% when compared with the normal weight concrete (NWC). The compressive strength of the developed LWC was sufficient to be used as structural concrete, particularly of those mixtures containing 10% and 15% perlite aggregate. The durability of LWC was comparable to NWC in terms of chloride diffusion and resistance of concrete to corrosion of reinforcing steel. The tangible outcomes also include the superior thermal insulation properties of LWC compared to NWC. The greater incorporation of EPA in the concrete resulted in better behavior under seismic loading.

scholarly journals Effect of Expanded Perlite Aggregate Size on Physical and Mechanical Properties of Ultra Lightweight Concrete Produced with Expanded Perlite Aggregate

2019 ◽  
Author(s):  
Mucip Tapan ◽  
Celil Engin
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Bending Strength ◽  
Lightweight Concrete ◽  
Unit Weight ◽  
Ultra Sound ◽  
Expanded Perlite ◽  
Freezing And Thawing ◽  
Freezing And Thawing Cycles

In this study, ultra-light weight concrete (ULWC) with heat-insulating properties is produced by using different size expanded perlite aggregates and various admixtures. The compressive strength, 4 point bending strength, freezing and thawing resistance, water absorption, dry unit weight, ultra sound velocities and thermal conductivity of the samples were determined by applying appropriate tests. The effect of different size expanded perlite aggregate on the properties of ULWC were also investigated in this study and it was found that as the expanded perlite aggregate diameter increased, the void volume uniformity, water absorption percentage and freezing-thawing resistance increased while the unit volume weight of ULWC samples, ultrasound speed velocities, thermal conductivity and compressive strength were decreased. The changes in the masses and compressive strength of ULWC samples subjected to freezing and thawing cycles were examined. The compressive strength loss was found to be between 5 % and 47 % while the weight loss was between 1 % and 3.5 % after 15 freezing and thawing cycles. Finally, the effects of the admixtures on the fresh properties of ULWC were examined and it was determined that the use of 4.5 kg of air-entraining material in one cubic meter of concrete mix is the most ideal ratio and the use of more than 0.01 % by volume of polypropylene fiber is caused settlements in fresh concrete mixtures.

Effects of Loading Percentage of Polyurethane in Lightweight Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1082-1085 ◽  
Author(s):  
Kamarul Aini Mohd Sari ◽  
Sohif Mat ◽  
Khairiah Haji Badri ◽  
Muhammad Fauzi Mohd Zain
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Lightweight Concrete ◽  
Palm Kernel ◽  
Physical And Mechanical Properties ◽  
Concrete Mixture ◽  
Experimental Program ◽  
Polymer Concrete ◽  
Optimum Level ◽  
Methylene Diphenyl Diisocyanate

An experimental program was performed to obtain the density, compressive strength, and thermal conductivity of palm-based lightweight concrete. Palm-based polyurethane (PU) particles were used as lightweight aggregates in creating concrete systems. Concrete systems contain palm kernel oil-based polyol (PKO-p) reacted with 2,4-methylene diphenyl diisocyanate (MDI). In this study, polymer concrete was improved to achieve the optimum level of PU with the lowest possible density. The PU particles in the concrete mixture comprised of 1% to 5% w/w with density of less than 1800 kg/m3. The PU particles were 5 mm in size. The ratio of PKO-p to MDI was set at 1:1 and the loading of the concrete mixture was set at 3% w/w to produce lightweight concrete. The resulting concrete has excellent compressive strength (17.5 MPa) and thermal conductivity (0.24 W/mK). Results show that the PU particle dosage has the most significant effect on the physical and mechanical properties of concrete.

scholarly journals Novel Core-Shell Non-Sintered Lightweight Aggregate Concrete for Better Properties in Wallboard

2021 ◽  
Author(s):  
Chaoming PANG ◽  
Xinxin MENG ◽  
Chunpeng ZHANG ◽  
Jinlong PAN
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Dry Density ◽  
Core Shell ◽  
Aggregate Concrete ◽  
The Core

Abstract Shrinkage of foam concrete can easily cause cracking and thus makes it difficult for a manufacturer to maintain quality. The density of lightweight aggregate concrete is too high to meet specifications for lightweight and thermal insulation for wallboard. Two types of concrete with dry density in the range 1000–1200 kg/m3 for use in wallboard were designed and prepared using foam and lightweight aggregate. The properties of porous lightweight aggregate concrete with core-shell non-sintered lightweight aggregate were compared with sintered lightweight aggregate concrete along with several dimensions. The two aggregates were similar in particle size, density, and strength. The effects of each aggregate on the workability, compressive strength, dry shrinkage, and thermal conductivity of the lightweight concrete were analyzed and compared. Pore structures were determined by mercury intrusion porosimetry and X-ray computed tomography. Compressive strength ranged from 7.8 to 11.8 MPa, and thermal conductivity coefficients ranged from 0.193 to 0.219 W/m/K for both types of concrete. The results showed that the core-shell non-sintered lightweight aggregate bonded better with the paste matrix at the interface transition zone and had a better pore structure than the sintered lightweight aggregate concrete. Slump flow of the core-shell non-sintered lightweight aggregate concrete was about 20% greater than that of the sintered lightweight aggregate concrete, 28d compressive strength was about 10% greater, drying shrinkage was about 10% less, and thermal conductivity was less. Porous lightweight aggregate concrete using core-shell non-sintered lightweight aggregate performs well when used in wallboard because of its low density, high thermal insulation, and improved strength.

Lightweight Concrete Precast Panels for the Improvement of Thermal Insulation of Housing with Expanded Polystyrene Beads

2021 ◽  
Vol 1033 ◽  
pp. 163-171
Author(s):  
Alexandra Reto ◽  
Renzo Sanabria ◽  
José Rodriguez ◽  
Alexandra Hinostroza
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Linear Trend ◽  
Precast Concrete ◽  
Expanded Polystyrene ◽  
Dry Density ◽  
Conventional Concrete ◽  
Polystyrene Beads

The precast concrete elements in the construction of buildings are increasingly used due to their better quality control, constructive speed, reduction of the number of workers and less waste of resources compared to conventional construction; for wall applications, to these advantages, the design to ensure thermal comfort requires the improvement of the low thermal insulation of conventional concrete panels. The use of materials with lower thermal conductivity such as Expanded PolyStyrene Beads (EPSB) in lightweight concrete for the construction of precast panels in housing, contributes to improve thermal insulation and the saving operational energy during its operation phase, because the aggregate has a small size, low density and thermal conductivity; applied in higher volumes in concrete, reduces indoor heat loss in cold climates and indoor heat gain in warm climates in housing. The purpose of this research is to study the behavior of lightweight concrete with EPSB for 16%, 26% and 36% addition and evaluate the air-dry density, compressive strength, thermal conductivity, relationship between air-dry density with compressive strength and thermal conductivity. The results indicate that the higher the percentage of EPSB the air-dry density, compressive strength and thermal conductivity decrease; the relationships between air-dry density with compressive strength and thermal conductivity follow a linear trend and are similar.

Orthogonal Experimental Study on Thermal Insulation Mortar Containing Mixed Ceramic Sand and Vitrified Micro Bead Aggregates

2012 ◽  
Vol 450-451 ◽  
pp. 659-662
Author(s):  
Zhi Lling Xie ◽  
Lin Zhu Sun ◽  
Fang Yang
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
High Performance ◽  
Orthogonal Experiments ◽  
Coefficient Of Thermal Conductivity ◽  
Mixed Ceramic ◽  
Relevant Factors ◽  
Density Coefficient

Mixed light aggregates can effectively reduce the coefficient of thermal conductivity of composite materials. Through orthogonal experiments of thermal insulation mortar containing mixed ceramic sand and vitrified micro bead aggregates, we analyzed the law of influence of relevant factors on the dry bulk density, coefficient of thermal conductivity and compressive strength of mortar containing mixed ceramic sand and vitrified micro bead aggregates and provided basic data for further improvement of such thermal insulation mortar so as to promote the development and application of high performance thermal insulation materials.

scholarly journals Replacement of Natural Sand with Expanded Vermiculite in Fly Ash-Based Geopolymer Mortars

2021 ◽  
Vol 11 (4) ◽  
pp. 1917
Author(s):  
Osman Gencel ◽  
Aliakbar Gholampour ◽  
Hayrettin Tokay ◽  
Togay Ozbakkaloglu
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Pulse Velocity ◽  
Unit Weight ◽  
Natural Sand ◽  
Dry Unit Weight ◽  
Expanded Vermiculite ◽  
Naoh Solution ◽  
Ultrasound Pulse

Increasing the thermal insulation of building components to reduce the thermal energy loss of buildings has received significant attention. Owing to its porous structure, using expanded vermiculite as an alternative to natural river sand in the development of building materials would result in improvement of the thermal performance of buildings. This study investigates the properties of fly ash (FA)-based geopolymer mortars prepared with expanded vermiculite. The main aim of this study was to produce geopolymer mortar with lower thermal conductivity than conventional mortar for thermal insulation applications in buildings. A total of twelve batches of geopolymers were prepared for evaluating their different properties. The obtained results show that, at a given FA and expanded vermiculite content, the geopolymers prepared with a 10 molar NaOH solution exhibited a higher flowability, water absorption and porosity, as well as a lower dry unit weight, compressive strength, ultrasound pulse velocity and thermal conductivity compared with those prepared with a 15 molar NaOH solution. As is also shown, the geopolymers containing expanded vermiculite (15%) developed a lower flowability (~6%), dry unit weight (~6%), compressive strength (~7%), ultrasound pulse velocity (~6%) and thermal conductivity (~18%), as well as a higher apparent porosity (~6%) and water absorption (~9%) compared with those without expanded vermiculite at a given FA content and NaOH concentration. The findings of this study suggest that incorporating expanded vermiculite in FA-based geopolymer mortar can provide eco-friendly and lightweight building composites with improved sound and thermal insulation properties, contributing toward the reduction of the environmental effects of waste materials and conservation of natural sand.

scholarly journals Feasibility of Producing Lightweight Concrete Using Indigenous Materials Without Autoclaving

1970 ◽  
Vol 3 ◽  
Author(s):  
M Shamsuddoha ◽  
MM Islam ◽  
MA Noor
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Lightweight Concrete ◽  
Absorption Capacity ◽  
Appropriate Technology ◽  
Unit Weight ◽  
Sequential Approach ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Volumetric Expansion

This research shows the feasibility and sequential approach for producing lightweight concrete without autoclaving using indigenous ingredients and appropriate technology of Bangladesh. Ingredients were mixed chronologically using trial-and-error method to reduce unit weight. Specific volume principle was utilized to observe the effect of inclusion of cement, water, sand, lime and aluminium in the mixture to achieve the goal. Molds were used to accommodate volumetric expansion of mixture. Both 50 mm and 150 mm cubic specimens were prepared for tests. Density and compressive strength were determined for specimens. Absorption capacity and thermal conductivity were also determined to get the product performance. From the results, it was seen that density and compressive decreased with increased water-cement ratio. Volumetric expansion was high for higher volume surface ratio. Finally, lightweight concrete with density, compressive strength and thermal conductivity within range of 700-1000 kg/m3, 0.5-2.0 MPa and 0.2-0.5 W/m-k respectively was produced. KEY WORDS: Volumetric expansion; Lightweight concrete; Water-cement ratio; Mix design. DOI: http://dx.doi.org/10.3329/mist.v3i0.8049

scholarly journals Structural Applications of Thermal Insulation Alkali Activated Materials with Reduced Graphene Oxide

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1052
Author(s):  
Wu-Jian Long ◽  
Can Lin ◽  
Xiao-Wen Tan ◽  
Jie-Lin Tao ◽  
Tao-Hua Ye ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Energy Consumption ◽  
Reduced Graphene Oxide ◽  
Thermal Insulation ◽  
Expanded Polystyrene ◽  
Information Modeling ◽  
Reduced Graphene ◽  
Structural Applications ◽  
Alkali Activated

Development of low thermal conductivity and high strength building materials is an emerging strategy to solve the heavy energy consumption of buildings. This study develops sustainable alkali activated materials (AAMs) for structural members from waste expanded polystyrene (EPS) beads and reduced graphene oxide (rGO) to simultaneously meet the thermal insulation and mechanical requirements of building energy conservation. It was found that the thermal conductivity of AAMs with 80 vol.% EPS and 0.04 wt.% rGO (E8–G4) decreased by 74% compared to the AAMs without EPS and rGO (E0). The 28-day compressive and flexural strengths of E8–G4 increased by 29.8% and 26.5% with the addition of 80 vol.% EPS and 0.04 wt.% rGO, compared to the sample with 80 vol.% EPS without rGO (E8). In terms of compressive strength, thermal conductivity, and cost, the efficiency index of E8–G4 was higher than those of other materials. A building model made from AAMs was designed using building information modeling (BIM) tools to simulate energy consumption, and 31.78% of total energy consumption (including heating and cooling) was saved in the building operation period in Harbin City, China. Hence, AAMs made of waste EPS beads and rGO can realize the structural and functional integrated application in the future.

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