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1 – 10 of 634Toqa AL-Kasasbeh and Rabab Allouzi
This research is part of a project that aims to investigate using foamed concrete structurally in houses. Foamed concrete has a porous structure that makes it light in weight…
Abstract
Purpose
This research is part of a project that aims to investigate using foamed concrete structurally in houses. Foamed concrete has a porous structure that makes it light in weight, good in thermal insulation, good in sound insulation and workable.
Design/methodology/approach
An experimental program is conducted in this research to investigate the behavior of polypropylene fiber reinforced foam concrete beams laterally reinforced with/without glass fiber grid.
Findings
The results proved the effectiveness and efficiency of using glass fiber grid as lateral reinforcements on the shear strength of reinforced foam concrete ribs, in reducing the cracks width and increasing its shear capacity, contrary to using glass fiber grid of reinforced foam concrete beams since glass fiber grid did not play good role in beams.
Originality/value
Limited literature is available regarding the structural use of foam concrete. However, work has been done in many countries concerning its use as insulation material, while limited work was done on structural type of foam concrete.
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Hanadi Al-Zubaidi and Rabab Allouzi
Cement can be replaced to reduce the energy consumption and the environmental impact of cement. Also, foamed concrete can be used structurally in residential buildings to reduce…
Abstract
Purpose
Cement can be replaced to reduce the energy consumption and the environmental impact of cement. Also, foamed concrete can be used structurally in residential buildings to reduce weight and improve thermal insulation. To achieve these two goals, this paper aims to investigate the effect of basalt powder as a partial replacement of either cement or sand.
Design/methodology/approach
This paper investigates the effect of basalt powder as a partial replacement of either cement or sand on the mechanical properties of foamed concrete used to cast slabs. First, mechanical properties of foamed concrete are tested with and without replacement of basalt. Then, six slabs of different thicknesses and mixes are investigated. The thicknesses considered are 150- and 200-mm slabs. The three mixes used to construct these slabs are foamed concrete with no basalt powder, foamed concrete with replacement of 20% of cement by basalt powder and foamed concrete with replacement of 20% of sand by basalt powder. The flexural behavior of these slabs is investigated.
Findings
All the slabs failed in the commonly intended flexural mode. The results show that the basalt powder acted as a strong filler material in the foamed concrete mix based on mechanical properties and flexural behavior. The proposed foamed concrete slabs can be used structurally in residential buildings.
Originality/value
A natural waste material that can be used to promote energy efficiency and reduce emission is basalt. In this paper, basalt powder is suggested to be used due to its chemical composition that is similar to cement. Also, basalt powder is low in cost as it is waste, while basalt aggregate is prepared, and it is only used as filler in paved roads. Accordingly, basalt is partially used instead of cement to reduce the emission of carbon dioxide that results from the cement manufacturing. Also, it is used as a partial alternative to sand which can be considered as a new stronger source as filling material used in the production of concrete.
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Irindu Upasiri, Chaminda Konthesingha, Anura Nanayakkara, Keerthan Poologanathan, Brabha Nagaratnam and Gatheeshgar Perampalam
In this study, the insulation fire ratings of lightweight foamed concrete, autoclaved aerated concrete and lightweight aggregate concrete were investigated using finite element…
Abstract
Purpose
In this study, the insulation fire ratings of lightweight foamed concrete, autoclaved aerated concrete and lightweight aggregate concrete were investigated using finite element modelling.
Design/methodology/approach
Lightweight aggregate concrete containing various aggregate types, i.e. expanded slag, pumice, expanded clay and expanded shale were studied under standard fire and hydro–carbon fire situations using validated finite element models. Results were used to derive empirical equations for determining the insulation fire ratings of lightweight concrete wall panels.
Findings
It was observed that autoclaved aerated concrete and foamed lightweight concrete have better insulation fire ratings compared with lightweight aggregate concrete. Depending on the insulation fire rating requirement of 15%–30% of material saving could be achieved when lightweight aggregate concrete wall panels are replaced with the autoclaved aerated or foamed concrete wall panels. Lightweight aggregate concrete fire performance depends on the type of lightweight aggregate. Lightweight concrete with pumice aggregate showed better fire performance among the normal lightweight aggregate concretes. Material saving of 9%–14% could be obtained when pumice aggregate is used as the lightweight aggregate material. Hydrocarbon fire has shown aggressive effect during the first two hours of fire exposure; hence, wall panels with lesser thickness were adversely affected.
Originality/value
Finding of this study could be used to determine the optimum lightweight concrete wall type and the optimum thickness requirement of the wall panels for a required application.
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Norashidah Abd Rahman, Siti Amirah Azra Khairuddin, Mohd Faris Faudzi, Mohd Harith Imran Mohd Asri, Norwati Jamaluddin and Zainorizuan Mohd Jaini
Concrete-filled hollow section (CFHS) is widely used in steel construction. The combination of concrete and steel decreases buckling and deformation of steel. However, studies…
Abstract
Purpose
Concrete-filled hollow section (CFHS) is widely used in steel construction. The combination of concrete and steel decreases buckling and deformation of steel. However, studies reveal that using normal concrete increases the dead weight of a structure. Therefore, a lightweight concrete, such as foamed concrete (FC), is proposed to reduce the weight of the structure. The purpose of this study is to determine the strength of modified fibrous foamed CFHS (FCFHS).
Design/methodology/approach
Steel and polypropylene fibres were used with rice husk ash, and short column fibrous FCFHSs were tested under compression load. Greased and non-greased methods were adopted to determine bond strength and confining effect between steel and concrete.
Findings
Results indicate that the use of fibre in FCFHSs improves the strength of CFHS from 9% to 11%. The non-greased method confirms that an interaction exists between steel and concrete with a confinement coefficient of more than 2.0.
Originality/value
It can be shown that the modified fibrous foamed concrete can increase the strength of the concrete and can be used as concrete filled in steel construction industry.
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Hong-Yu Yao, Xiang-Jun Kong, Ya-Jie Shi, Xian-Bo Xiao and Ning-Ning Le
Engineered material arresting systems (EMASs) are dedicated to stopping aircraft that overrun the runway before they enter dangerous terrain. The system consists of low-strength…
Abstract
Purpose
Engineered material arresting systems (EMASs) are dedicated to stopping aircraft that overrun the runway before they enter dangerous terrain. The system consists of low-strength foamed concretes. The core component of the arresting system design is a reliable simulation model. Aircraft test verification is required before the practical application of the model. This study aims to propose a simulation model for the arresting system design and conducts serial verification tests.
Design/methodology/approach
Six verification tests were conducted using a Boeing 737 aircraft. The aircraft was equipped with an extra inertia navigation system and a strain gauge system to measure its motion and the forces exerted on the landing gears. The heights of the arrestor beds for these tests were either 240 or 310 mm, and the entering speeds of the aircraft ranged from 23.9 to 60.6 knots.
Findings
Test results revealed that both the aircraft and the pilots on board were safe after the tests. The maximum transient acceleration experienced by the dummies on board was 2.5 g, which is within the human tolerance. The model exhibited a satisfied accuracy to the field tests, as the calculation errors of the stopping distances were no greater than 7 per cent.
Originality/value
This study proposes a simulation model for the arresting system design and conducts serial verification tests. The model can be used in EMAS design.
Details
Keywords
Samer S. Abdulhussein, Izwan Johari and Nada Mahdi Fawzi
This paper aims to produce lightweight concrete by combining aerated concrete with expanded polystyrene beads concrete to create structural aerated-polystyrene lightweight concrete…
Abstract
Purpose
This paper aims to produce lightweight concrete by combining aerated concrete with expanded polystyrene beads concrete to create structural aerated-polystyrene lightweight concrete that satisfies the criteria of sustainability for thermal and sound insulation properties and the structural criteria of having satisfactory compressive strength for structural elements.
Design/methodology/approach
The experimental study was carried out to reach the largest compressive strength while maintaining the lowest possible density by preparing nine mixes of concrete, involving different ratios of aluminum waste powder and polystyrene beads as 0%, 0.2% and 0.3% and 0%, 0.1% and 0.2%, respectively, by weight of cement to produce the lightweight concrete with different densities. The performance of mechanical properties, thermal conductivity, ultrasonic pulse velocity, density, modulus of elasticity, acoustic impedance and scanning electron microscopy were studied and discussed.
Findings
Results showed that aerated-expended polystyrene beads concrete had the most suitable properties when the proportions of aluminum waste powder and expanded polystyrene beads were 0.2% and 0.1%, respectively. The compressive strength, density, thermal conductivity and acoustic impedance were 38.5 MPa, 1,768 Kg/m3, 0.358 W/(m.k) and 4.91 Kg/m2 s, respectively.
Originality/value
The experimental work was done using aluminum scrap waste powder as an expanding agent to produce aerated concrete and combining it with expanded polystyrene bead concrete to produce structural aerated-polystyrene concrete, which contains fine materials (silica fume and local natural raw limestone) and superplasticizers.
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Irindu Upasiri, Chaminda Konthesingha, Anura Nanayakkara, Keerthan Poologanathan, Gatheeshgar Perampalam and Dilini Perera
Light-Gauge Steel Frame (LSF) structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel…
Abstract
Purpose
Light-Gauge Steel Frame (LSF) structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel lipped channel sections negative fire performance, cavity insulation materials are utilized in the LSF configuration to enhance its fire performance. The applicability of lightweight concrete filling as cavity insulation in LSF and its effect on the fire performance of LSF are investigated under realistic design fire exposure, and results are compared with standard fire exposure.
Design/methodology/approach
A Finite Element model (FEM) was developed to simulate the fire performance of Light Gauge Steel Frame (LSF) walls exposed to realistic design fires. The model was developed utilising Abaqus subroutine to incorporate temperature-dependent properties of the material based on the heating and cooling phases of the realistic design fire temperature. The developed model was validated with the available experimental results and incorporated into a parametric study to evaluate the fire performance of conventional LSF walls compared to LSF walls with lightweight concrete filling under standard and realistic fire exposures.
Findings
Novel FEM was developed incorporating temperature and phase (heating and cooling) dependent material properties in simulating the fire performance of structures exposed to realistic design fires. The validated FEM was utilised in the parametric study, and results exhibited that the LSF walls with lightweight concrete have shown better fire performance under insulation and load-bearing criteria in Eurocode parametric fire exposure. Foamed Concrete (FC) of 1,000 kg/m3 density showed best fire performance among lightweight concrete filling, followed by FC of 650 kg/m3 and Autoclaved Aerated Concrete (AAC) 600 kg/m3.
Research limitations/implications
The developed FEM is capable of investigating the insulation and load-bearing fire ratings of LSF walls. However, with the availability of the elevated temperature mechanical properties of the LSF wall, materials developed model could be further extended to simulate the complete fire behaviour.
Practical implications
LSF structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel-lipped channel sections negative fire performance, cavity insulation materials are utilised in the LSF configuration to enhance its fire performance. The lightweight concrete filling in LSF is a novel idea that could be practically implemented in the construction, which would enhance both fire performance and the mechanical performance of LSF walls.
Originality/value
Limited studies have investigated the fire performance of structural elements exposed to realistic design fires. Numerical models developed in those studies have considered a similar approach as models developed to simulate standard fire exposure. However, due to the heating phase and the cooling phase of the realistic design fires, the numerical model should incorporate both temperature and phase (heating and cooling phase) dependent properties, which was incorporated in this study and validated with the experimental results. Further lightweight concrete filling in LSF is a novel technique in which fire performance was investigated in this study.
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Parvathidevi A. and Naga Satish Kumar Ch
This study aims to assess the efficacy of thermal analysis of concrete slabs by including different insulation materials using ANSYS. Regression equations were proposed to predict…
Abstract
Purpose
This study aims to assess the efficacy of thermal analysis of concrete slabs by including different insulation materials using ANSYS. Regression equations were proposed to predict the thermal conductivity using concrete density. As these simulation and regression analyses are essential tools in designing the thermal insulation concretes with various densities, they sequentially reduce the associated time, effort and cost.
Design/methodology/approach
Two grades of concretes were taken for thermal analysis. They were designed by replacing the natural fine aggregates with thermal insulation aggregates: expanded polystyrene, exfoliated vermiculite and light expanded clay. Density, temperature difference, specific heat capacity, thermal conductivity and time were measured by conducting experiments. This data was used to simulate concrete slabs in ANSYS. Regression analysis was performed to obtain the relation between density and thermal conductivity. Finally, the quality of the predicted regression equations was assessed using root mean square error (RMSE), mean absolute error (MAE), integral absolute error (IAE) and normal efficiency (NE).
Findings
ANSYS analysis on concrete slabs accurately estimates the thermal behavior of concrete, with lesser error value ranges between 0.19 and 7.92%. Further, the developed regression equations proved accurate with lower values of RMSE (0.013 to 0.089), MAE (0.009 to 0.088); IAE (0.216 to 5.828%) and higher values of NE (94.16 to 99.97%).
Originality/value
The thermal analysis accurately simulates the experimental transfer of heat across the concrete slab. Obtained regression equations proved helpful while designing the thermal insulation concrete.
Details
Keywords
Manuel Jesus, Ana Sofia Guimarães, Bárbara Rangel and Jorge Lino Alves
The paper seeks to bridge the already familiar benefits of 3D printing (3DP) to the rehabilitation of cultural heritage, still based on the use of complex and expensive…
Abstract
Purpose
The paper seeks to bridge the already familiar benefits of 3D printing (3DP) to the rehabilitation of cultural heritage, still based on the use of complex and expensive handcrafted techniques and scarce materials.
Design/methodology/approach
A compilation of different information on frequent anomalies in cultural heritage buildings and commonly used materials is conducted; subsequently, some innovative techniques used in the construction sector (3DP and 3D scanning) are addressed, as well as some case studies related to the rehabilitation of cultural heritage building elements, leading to a reflection on the opportunities and challenges of this application within these types of buildings.
Findings
The compilation of information summarised in the paper provided a clear reflection on the great potential of 3DP for cultural heritage rehabilitation, requiring the development of new mixtures (lime mortars, for example) compatible with the existing surface and, eventually, incorporating some residues that may improve interesting properties; the design of different extruders, compatible with the new mixtures developed and the articulation of 3D printers with the available mapping tools (photogrammetry and laser scanning) to reproduce the component as accurately as possible.
Originality/value
This paper sets the path for a new application of 3DP in construction, namely in the field of cultural heritage rehabilitation, by identifying some key opportunities, challenges and for designing the process flow associated with the different technologies involved.
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Aya Qatawna, Rabab Allouzi and Samih Qaqish
The primary objective of this study is to produce one-way slabs made of LWFC with low density and sufficient compressive strength suitable for structural purpose then investigate…
Abstract
Purpose
The primary objective of this study is to produce one-way slabs made of LWFC with low density and sufficient compressive strength suitable for structural purpose then investigate their flexural behavior under various types of reinforcement and thickness of the slab and the influence of addition of PP fibers reinforcement on the mechanical behavior of reinforced concrete slabs. The specimens were tested using four-point loading. The results concerning load capacity, deflection and failure mode and crack pattern for each specimen were obtained. Also, an analytical investigation of PP fiber and GFG contribution on the flexural behavior of foamed concrete slabs is studied to investigate the significant role of PP fiber on the stress distribution in reinforced foam concrete and predict the flexural moment capacity.
Design/methodology/approach
The materials used in this study are cement, fine aggregate (sand), water, PP fibers, foaming agent, chemical additives if required, steel reinforcing rebars and glass fiber grid. The combination of these constituent materials will be used to produce foamed concrete in this research Then this study will present the experimental program of one-way foamed concrete slabs including slabs reinforced with GFR grids and another with steel reinforcements. The slabs will be tested in the laboratory under static loading conditions to investigate their ultimate capacities. The flexural behavior is to the interest of the slabs reinforced with GFR grids reinforcements in comparison with that of one with steel reinforcing rebars. Three groups are considered. (1) Group I: two slabs of PP fiber foamed concrete with minimum required reinforcements. (2) Group II: two slabs of PP fiber foamed concrete with glass fiber grids. (3) Group III: two slabs of PP fiber foamed concrete with the minimum required reinforcements and glass fiber grids.
Findings
The experimental results proved the effectiveness and efficiency of this the new system in producing a low density of concrete below 1900 kg/m3 had a corresponding strength of about 17 MPa at least. Besides, the presence of PP fibers had a noticeable improvement on the flexural strength values for all the examined slabs. It was found that the specimens reinforced with steel reinforcement mesh carried higher flexural capacity compared to these reinforced with GFG only. The specimens reinforced with GFG exhibited the lowest flexural capacity due to GFG separation from the concrete substrate. Also, an analytical investigation to predict the flexural strength of all tested specimens was carried out. The analytical results were agreed with the experimental results. Therefore, LWFC can be used as a substitute lightweight concrete material for the production of structural concrete applications in the construction industries today.
Research limitations/implications
Foamed concrete is a wide field to discuss. To achieve the objectives of the project, the study is focused on the foamed concrete with the following limitations: (1) because the aim of this research is to produce foamed concrete suitable for structural purposes, it is decided to produce mixes within the density range 1300–1900 kg/m3. (2) Simply-supported slabs are of considered. (3) This study also looks out by using GFR and without it.
Originality/value
The main objectives of this study were producing structural foamed concrete slabs and investigate their flexural response for residential uses.
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