scholarly journals Some Engineering Properties of Foamed Concrete for Sustainable Technological Development

2021 ◽  
Vol 6 (3) ◽  
pp. 53-57
Author(s):  
Felix A. Oginni ◽  
Samuel N. John
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Comparative Study ◽  
Modulus Of Elasticity ◽  
Technological Development ◽  
Drying Shrinkage ◽  
Engineering Properties ◽  
Dry Density ◽  
Concrete Production ◽  
Foamed Concrete

A study of the technology of foamed concrete production is carried out. The engineering properties and applications of this type of concrete are presented for varying densities so as to effectively tap the advantages of its use for specific purposes. The properties considered are the 7-day compressive strength, thermal conductivity, modulus of elasticity and drying shrinkage. A study of the behaviours of foamed concrete at varying dry densities for the different characteristics was undertaken. Results indicate that as the dry density increases, the engineering properties increase though at different rates for the 7-day Compressive strength, Thermal conductivity, and Modulus of elasticity. The drying shrinkage decreases as the dry density increases. A comparative study of the 7-day Compressive strength and Modulus of elasticity show that they both follow the same trend over the varying dry density except at a dry density of 1200 kg/m3. A comparative study of the thermal conductivity and the percent drying shrinkage indicate that the thermal conductivity is inversely proportional to the percent drying shrinkage. Economics and other considerations together with its multipurpose applications of foamed concrete can open up business opportunities in Africa and sustainability. This can also help in providing needed funds for infrastructural development.

scholarly journals Performance Evaluation of Pre-foamed Ultra-lightweight Composites Incorporating Various Proportions of Slag

2020 ◽  
Author(s):  
Trong-Phuoc Huynh ◽  
Van-Hien Pham ◽  
Ngoc-Duy Do ◽  
Trong-Chuc Nguyen ◽  
Nguyen-Trong Ho
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Drying Shrinkage ◽  
Engineering Properties ◽  
Dry Density ◽  
Brick Wall ◽  
River Sand ◽  
Microstructure Observation ◽  
Granulated Blast Furnace Slag

This research examines the feasibility of using a mixture of cement, fly ash, ground granulated blast-furnace slag, and river sand to manufacture pre-foamed ultra-lightweight composite (PULC). Four PULC specimens were prepared with the substitution of cement by slag at 0, 10, 20, and 30 % by weight. The engineering properties of PULC samples were evaluated through the tests of compressive strength, dry density, water absorption, drying shrinkage, and thermal conductivity. Besides, numerical simulation of heat transfer through the PULC brick wall and the microstructure observation were performed. The performance of PULC mixtures incorporating slag showed higher effectiveness than merely used cement. The substitution of 20 % cement by slag resulted in the highest compressive strength as well as the lowest value of water absorption of the PULC samples. Also, the efficiency of the thermal conductivity was in inverse proportion with the density of PULC specimens and it was right for water absorption and drying shrinkage. Moreover, numerical simulations showed that the temperature distribution values in the wall made by PULC material were smaller than in the wall made by the normal clay brick in the same position. Besides, the microstructure analysis revealed that the existence of slag generated a more dense structure of PULC samples with the addition of calcium-silicate-hydrate (C-S-H) gel, especially for a mix containing 20 % slag. Thus, the results of this study further demonstrated that a 20 % slag was the optimal content for the good engineering properties of the PULC samples.

Research on the Foamed Concrete with High Volume Fly Ash

2017 ◽  
Vol 727 ◽  
pp. 1062-1066
Author(s):  
Hui Chao Chu ◽  
Xian Jun Lyu ◽  
Yan Zhang
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Process Parameters ◽  
High Volume ◽  
Dry Density ◽  
High Volume Fly Ash ◽  
Foamed Concrete

A study has been undertaken to investigate the effects, on the properties of foamed concrete, of replacing large volumes of cement with fly ash. This paper reports the results of the properties of foamed concrete and shows that up to 55% of the cement could be replaced without any significant reduction in compressive strength. Foamed concrete with 55% fly ash and good performance were obtained by optimizing the process parameters. The results showed that the compressive strength, dry density, water absorption and thermal conductivity of foamed concrete with 55% fly ash were 0.71MPa, 244kg/m3, 33%, and 0.045 W/mK respectively.

Properties of Foamed Lightweight Material Produced Using Blended Cement-Limestone Powder

2017 ◽  
Vol 909 ◽  
pp. 280-285
Author(s):  
Trong Phuoc Huynh ◽  
Chao Lung Hwang
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
Close Correlation ◽  
Limestone Powder ◽  
Engineering Properties ◽  
Dry Density ◽  
Test Results ◽  
Lightweight Material

The present study aims to investigate the engineering properties of foam lightweight material (FLM) that was produced using a mixture of ordinary Portland cement (OPC) and limestone powder (LP). The FLM samples were prepared with various proportions of LP (10%, 20%, and 30%) and different percentages of foam (9%, 12%, and 15%). Properties of the FLM were evaluated through the values of compressive strength, dry density, porosity, and thermal conductivity. Test results show that the foam contents affected all properties of the FLM significantly, whereas LP contents showed the insignificant effect to the FLM properties. Furthermore, the results of the present study showed a close correlation between porosity and other properties of the FLM as higher porosity resulted in lower density and thus lower thermal conductivity and mechanical strength.

Effect of Unit Binder Content on Mechanical Properties of Foamed Concrete

2014 ◽  
Vol 692 ◽  
pp. 486-489
Author(s):  
Kyung Ho Lee ◽  
Keun Hyeok Yang
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
High Performance ◽  
Binder Content ◽  
Dry Density ◽  
Steam Curing ◽  
Pressure Steam ◽  
Foamed Concrete ◽  
Aerated Concrete ◽  
Test Result

The present study tested six concrete mixes to develop a high-performance foamed concrete without using high-pressure steam curing processes, as an alternative to autoclaved aerated concrete (AAC) blocks. Dry density, compressive strength and thermal conductivity of foamed concrete were measured according to the variation of unit binder content. Test result showed that dry denstiy, compressive strength and thermal conductivity of foamed concrete incresed with the increase in the unit binder content. The compressive strength of tested foamed concrete was commonly higher than that of conventional foamed concrete with the same dry density.

scholarly journals Effect of Polypropylene Fibres on the Thermal Conductivity of Lightweight Foamed Concrete

2018 ◽  
Vol 150 ◽  
pp. 03008 ◽  
Author(s):  
Ashfaque Ahmed Jhatial ◽  
Wan Inn Goh ◽  
Noridah Mohamad ◽  
U. Johnson Alengaram ◽  
Kim Hung Mo
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Urban Areas ◽  
Dry Density ◽  
Polypropylene Fibres ◽  
Conventional Concrete ◽  
Thermal Insulating ◽  
Foamed Concrete ◽  
Permanent Load

With the reduction in the permanent load on the structure and excellent insulation properties, the lightweight foamed concrete is a potential thermal insulating building material to counter the urban heat island effect, which increases the temperature of urban areas due to the concentration of infrastructures constructed using conventional concrete that absorbs the solar radiation. The lightweight foamed concrete whose dry density ranges from 400 kg/m3 to 1600 kg/m3, has lower thermal conductivity compared to conventional concrete. But reduced density attributes to reduced compressive strength. In this study, to enhance the mechanical properties, the foamed concrete of 1600 kg/m3 density is reinforced with polypropylene fibres (PP). Four percentages of PP fibres, 0% (controlled), 0.2%, 0.25% and 0.30% were added into the foamed concrete. The compressive strength as well as the thermal conductivity of foamed concrete reinforced with PP fibres were determined. Based upon the findings, the optimum percentage of PP was determined to be 0.20% which gave higher compressive strength while thermal conductivity of foamed concrete was observed to decrease upon addition of PP fibres. Thus, addition of PP fibres improves the thermal resistance in the foamed concrete along with enhancing the mechanical properties.

scholarly journals Preparation and Characterization of Ultra-Lightweight Foamed Concrete Incorporating Lightweight Aggregates

2019 ◽  
Vol 9 (7) ◽  
pp. 1447 ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Mohamed El Madawy ◽  
Sang-Yeop Chung ◽  
Pawel Sikora ◽  
Dietmar Stephan
Keyword(s):  
Thermal Conductivity ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
Strength Development ◽  
Dry Density ◽  
Low Density ◽  
Wide Range ◽  
Fresh State ◽  
Foamed Concrete ◽  
Hardened State

Increasing interest is nowadays being paid to improving the thermal insulation of buildings in order to save energy and reduce ecological problems. Foamed concrete has unique characteristics and considerable potential as a promising material in construction applications. It is produced with a wide range of dry densities, between 600 and 1600 kg/m3. However, at a low density below 500 kg/m3, it tends to be unstable in its fresh state while exhibiting high drying shrinkage in its hardened state. In this study, lightweight aggregate-foamed concrete mixtures were prepared by the addition of preformed foam to a cement paste and aggregate. The focus of the research is the influence of fly ash, as well as fine lightweight aggregate addition, on the properties of foamed concrete with a density lower than 500 kg/m3. Concrete properties, including stability and consistency in the fresh state as well as thermal conductivity and mechanical properties in the hardened state, were evaluated in this study. Scanning electron microscopy (SEM) was used to study the microstructure of the foamed concrete. Several mixes with the same density were prepared and tested. The experimental results showed that under the same bulk density, incorporation of fine lightweight aggregate has a significant role on compressive strength development, depending on the characteristics of the lightweight aggregate. However, thermal conductivity is primarily related to the dry density of foamed concrete and only secondarily related to the aggregate content. In addition, the use of fine lightweight aggregate significantly reduces the drying shrinkage of foamed concrete. The results achieved in this work indicate the important role of lightweight aggregate on the stability of low-density foamed concrete, in both fresh and hardened states.

scholarly journals Experimental Study on the Effect of Water on the Properties of Cast In Situ Foamed Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Wenhui Zhao ◽  
Qian Su ◽  
Wubin Wang ◽  
Lele Niu ◽  
Ting Liu
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Moisture Content ◽  
Water Level ◽  
Immersion Time ◽  
Drying Shrinkage ◽  
Dry Density ◽  
Volumetric Moisture Content ◽  
Foamed Concrete

This study aims to investigate the effect of water on the properties of cast in situ foamed concrete with a dry density of 300–800 kg/m3 (100 kg/m3 is a gradient). Firstly, the shrinkage deformation with the curing time and the volumetric moisture content is studied by the drying shrinkage test and improved drying shrinkage test. Secondly, the influence of volumetric moisture content on mechanical properties is assessed. At last, the effects of immersion time and immersion type on the mechanical properties of foamed concrete are studied by considering the water-level conditions. The achieved results show that the shrinkage deformations increase with the curing time for the drying shrinkage test and the improved drying shrinkage test, while the variations are different. The shrinkage deformation increases with the decrease of volumetric moisture content for six dry densities of foamed concrete. Besides, it gradually changes in the early stage, while it changes fast in the later stage. The compressive strength and elastic modulus decrease with the increase of volumetric moisture content for each density. For the water-level unchanged condition, the compressive strength and elastic modulus initially decrease and then slowly increase with the increase of the immersion time. For the water-level changed condition, the compressive strength and elastic modulus of foamed concrete decrease with the increase of immersion time for each dry density, and the rate of early attenuation is high, whereas the rate of later attenuation is limited.

scholarly journals Experimental Investigation of the Production of Sustainable Lightweight Concrete

2020 ◽  
Vol 38 (11A) ◽  
pp. 1652-1665
Author(s):  
Mouhammed J. Lafta
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Dry Density ◽  
Normal Concrete ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Concrete Production ◽  
Concrete Mix

An experimental study on four types of coarse aggregate was conducted to produce lightweight concrete. These four types are namely; white limestone, red limestone, clay brick fragments, and pumice. Ordinary Portland cement was used for all examined mixes. Water to cement ratio (w/c) was modified according to the effect of coarse aggregate type on the workability of the resulted concrete for each mix. The reference concrete mix, which is normal concrete, water to cement ratio used was (0.5). The investigated characteristics for all concrete mixes were workability, compressive strength, dry density, absorption, and thermal conductivity. Results indicated that the aggregate type significantly affects most of the properties of lightweight concrete mixes such as workability, density, and thermal insulation for all tested types of concrete. All investigated specimens indicated improvement in terms of density, workability, and thermal conductivity when compared to the reference concrete mix. Yet, it was derived from the testing results that using pumice in lightweight concrete production is the optimum option among the other examined types. When compared to normal concrete, this type of lightweight concrete showed a 41% decrease in dry density, nearly 72.54% decrease in thermal conductivity, and about 12% increase in workability. However, it is vital to notice that due to the low compressive strength and the relatively high absorption capability for all the examined types of lightweight concrete, it is suggested to use these types of concrete for non-structural walls that are not subjected to or exposed to high humidity.

The influence of the addition of ground olive stone on the thermo-mechanical behavior of compressed earth blocks

2020 ◽  
Vol 108 (2) ◽  
pp. 203
Author(s):  
Samia Djadouf ◽  
Nasser Chelouah ◽  
Abdelkader Tahakourt
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Mechanical Behavior ◽  
Agricultural Waste ◽  
Hydraulic Press ◽  
Dry Density ◽  
Olive Stone ◽  
Compressed Earth Blocks ◽  
Clay Matrix ◽  
Earth Blocks

Sustainable development and environmental challenges incite to valorize local materials such as agricultural waste. In this context, a new ecological compressed earth blocks (CEBS) with addition of ground olive stone (GOS) was proposed. The GOS is added as partial clay replacement in different proportions. The main objective of this paper is to study the effect of GOS levels on the thermal properties and mechanical behavior of CEB. We proceeded to determining the optimal water content and equivalent wet density by compaction using a hydraulic press, at a pressure of 10 MPa. The maximum compressive strength is reached at 15% of the GOS. This percentage increases the mechanical properties by 19.66%, and decreases the thermal conductivity by 37.63%. These results are due to the optimal water responsible for the consolidation and compactness of the clay matrix. The substitution up to 30% of GOS shows a decrease of compressive strength and thermal conductivity by about 38.38% and 50.64% respectively. The decrease in dry density and thermal conductivity is related to the content of GOS, which is composed of organic and porous fibers. The GOS seems promising for improving the thermo-mechanical characteristics of CEB and which can also be used as reinforcement in CEBS.

scholarly journals The performance of ultra-lightweight foamed concrete incorporating nanosilica

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Pawel Sikora ◽  
Sang-Yeop Chung ◽  
Dietmar Stephan
Keyword(s):  
Wall Thickness ◽  
Probabilistic Approach ◽  
Drying Shrinkage ◽  
Dry Density ◽  
Optimal Dosage ◽  
X Ray ◽  
Mechanical And Physical Properties ◽  
Fresh State ◽  
Foamed Concrete ◽  
The Stability

AbstractThis paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m3, in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as cement replacing materials, to compare their influence on the properties of foamed concrete. Mechanical and physical properties, drying shrinkage and the sorption of concrete were measured. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (µ-CT) and a probabilistic approach were implemented to evaluate the microstructural changes associated with the incorporation of different additives, such as wall thickness and pore anisotropy of produced ULFCs. The experimental results confirmed that the use of NS in optimal dosage is an effective way to improve the stability of foam bubbles in the fresh state. Incorporation of NS decrease the pore anisotropy and allows to produce a foamed concrete with increased wall thickness. As a result more robust and homogenous microstructure is produced which translate to improved mechanical and transport related properties. It was found that replacement of cement with 5 wt.-% and 10 wt.-% NS increase the compressive strength of ULFC by 20% and 25%, respectively, when compared to control concrete. The drying shrinkage of the NS-incorporated mixes was higher than in the control mix at early ages, while decreasing at 28 d. In overall, it was found that NS is more effective than other conventional fine materials in improving the stability of fresh mixture as well as enhancing the strength of foamed concrete and reducing its porosity and sorption.

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