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Article
Publication date: 14 October 2021

Hala Mohamed Elkady, Ola M. Bakr, Mohamed Kohail and Elsayed Abdel Raouf Nasr

This paper presents the second part of the investigation on resistance to elevated temperatures of a proposed hybrid composite concrete (NCSF-Crete) mix. The composite…

Abstract

Purpose

This paper presents the second part of the investigation on resistance to elevated temperatures of a proposed hybrid composite concrete (NCSF-Crete) mix. The composite including nano metakaolin (NC) and steel fibers (SF) in addition to regular concrete components has proven -in the first published part-earlier promoted fresh concrete behavior, and to have reduced loss in compressive strength after exposure to a wide range of elevated temperatures. This presented work evaluates another two critical mechanical characteristics for the proposed composite -namely- splitting and bond strengths.

Design/methodology/approach

A modified formula correlating splitting and compressive strength (28 days) based on experiments results for NCSF is proposed and compared to formulas derived for regular concrete in different design codes. Finally, both spitting and bond strengths are evaluated pre- and post-exposure to elevated temperatures reaching 600 °C for two hours.

Findings

The proposed NCSF-Crete shows remarkable fire endurance, especially in promoting bond strength as after 600 °C heat exposure tests, it maintained strength equivalent to 70% of a regular concrete control mix at room temperature. Improving residual splitting strength was very significant up to 450 °C exposure.

Research limitations/implications

Obvious deterioration is monitored in splitting resistance for all concretes at 600 °C.

Practical implications

This proposed composite improved elevated heats resistance of the most significant concrete mechanical properties.

Social implications

Using a more green and sustainable constituents in the composite.

Originality/value

The proposed composite gathers the merits of using NC and SF, each has been investigated separately as an addition to concrete mixes.

Details

Journal of Structural Fire Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 27 September 2021

Radhia Chabbi, Noureddine Ferhoune and Fouzia Bouabdallah

This research aims to study the materials that compose older reinforced concrete bridges which are damaged and degrading to explain the mechanisms and origins of various…

Abstract

Purpose

This research aims to study the materials that compose older reinforced concrete bridges which are damaged and degrading to explain the mechanisms and origins of various disorders. Therefore, this work will contribute to providing answers on the capacity of nondestructive evaluation method during the diagnosis. In addition to the characterization of affected structures, it will aim to provide effective solutions for different serious pathologies.

Design/methodology/approach

In this context, two bridges located on NH16 and NH21, respectively, were studied in Annaba city (north-east Algeria), specifically in El-Hadjar municipality located in the central industrial zone of Pont-Bouchet. This study makes it possible to make conclusions from the in-depth diagnosis based on disorders exposition causes and mechanical characteristics evolution by non-destructive testing (NDT) tools. Furthermore, solutions are proposed, including conservation maintenance of these degraded structures.

Findings

All degradations can be the result of several factors: either human (poor design) or chemical (surface water, wastewater and groundwater quality (acidic or basic)). In addition to other natural causes (geological formations, flood phenomena or climate), NDT tools play a major role in the evaluating mechanical performance of degraded structures (resistance and hardness).

Research limitations/implications

The NDT techniques can be transmitted to civil engineering experts because their training is limited regarding mechanical and structural construction.

Practical implications

NDT tools are the most suitable for in-situ assessing, and the concrete constructions health state, so far from financial problems.

Social implications

Degraded bridge diagnosis by NDT testing is necessary for a thorough safety evaluation (mechanical performance, strength and deformability), to protect human lives and design durability.

Originality/value

This is an original paper which contains new information at different scales and from special fields, based on an evaluation using NDT tools on real degraded structures. It can be used to improve the knowledge of materials employed in a bridge without performing expensive direct tests or the need for destroying it.

Details

International Journal of Building Pathology and Adaptation, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2398-4708

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Article
Publication date: 14 October 2021

Mohammed Seghir Ammari, Mohammed Bachir Tobchi, Yahia Amrani, Anouer Mim, Madani Bederina and Ahmida Ferhat

This study is part of the valorization of local materials and the reuse of industrial waste in construction. This study aims to improve the physical-mechanical properties…

Abstract

Purpose

This study is part of the valorization of local materials and the reuse of industrial waste in construction. This study aims to improve the physical-mechanical properties of sand concrete. This work is a continuation of previous studies conducted on sand concrete, the purpose of which is to introduce industrial waste into this material. For this purpose, a glass waste in powder form is added.

Design/methodology/approach

This study is focused on the effect of adding glass powder (GP) whose mass percentage varies from 0 to 40% with an interval of 10% to target the right composition that ensures the best compromise between the characteristics studied.

Findings

The results found show that the workability and density of the studied concretes decreased with increasing GP dosage. Indeed, the optimal addition which constitutes the best compromise between the studied properties is 10% of GP. Improvements of up to about 9% in the case of flexural strength and about 18% in the case of compressive strength. The thermal conductivity has been reduced by 12.74%, the thermal diffusivity which characterizes the notion of thermal inertia has been reduced by about 4% and the specific heat mass has been reduced by 7.80%. Also, the shrinkage has been reduced by about 20%. The microstructure of the studied composite shows a good homogeneity between the aggregates. Finally, the addition of GP to sand concrete gives very encouraging results.

Originality/value

The interest of this study is in two parts. The first one is the exploitation of local materials: dune sand, river sand and limestone filler to meet the growing demand for construction materials. And the second one is the reuse of glass waste, in the form of powder (GP), to solve the environmental problem. All this participates in the improvement of the physical-mechanical properties of sand concrete and the extent of its response to the development of an economical structural concrete.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 23 January 2020

Uchechi G. Eziefula, Hyginus E. Opara and Bennett I. Eziefula

This paper aims to investigate the 28-day compressive strength of concrete produced with aggregates from different sources.

Abstract

Purpose

This paper aims to investigate the 28-day compressive strength of concrete produced with aggregates from different sources.

Design/methodology/approach

Coarse aggregates were crushed granite and natural local stones mined from Umunneochi, Lokpa and Uturu, Isuakwato, respectively, in Abia State, Nigeria. Fine aggregate (river sand) and another coarse aggregate (river stone) were dredged from Otammiri River in Owerri, Imo State, Nigeria. The nominal mix ratios were 1:1:2, 1:2:4 and 1:3:6, whereas the respective water–cement ratios were 0.45, 0.5, 0.55 and 0.6.

Findings

The compressive strength of granite concrete, river stone concrete and local stone concrete ranged 17.79-38.13, 15.37-34.57 and 14.17-31.96 N/mm2, respectively. Compressive strength was found to increase with decreasing water–cement ratio and increasing cement content.

Practical implications

Granite concrete should be used in reinforced-concrete construction, especially when a cube compressive strength of 30 N/mm2 or higher is required.

Originality/value

Granite concrete exceeded the target compressive strength for all the concrete specimens, whereas river stone concrete and local stone concrete failed to achieve the target strength for some mix proportions and water–cement ratios.

Details

Journal of Engineering, Design and Technology , vol. 18 no. 5
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 1 June 2020

Hakas Prayuda, Fanny Monika and Martyana Dwi Cahyati

This study aims to discuss the results of fresh properties and compressive strength of self-compacting concrete using ingredients added red brick powder as a fine…

Abstract

Purpose

This study aims to discuss the results of fresh properties and compressive strength of self-compacting concrete using ingredients added red brick powder as a fine aggregate substitute. The results of the study were compared with the properties of fresh properties and compressive strength with ingredients added by rice husk ash, which is also a fine aggregate substitute. In addition, the initial compressive strength of each of these variations was also examined to accelerate the completion time of construction projects using self-compacting concrete.

Design/methodology/approach

This research was conducted in a laboratory by testing the characteristics of fresh and hardened properties of self-compacting concrete.

Findings

Fresh properties testing is carried out in the form of V-funnel, flow table, J-ring and L-box where all specimens produce quite varied flow rates. Compressive strength was estimated at ages 3, 7, 14 and 28 days with cylindrical specimens with a diameter of 150 mm and a height of 300 mm. The variation of fine aggregate substitutes used is 20, 40 and 60 per cent.

Originality/value

From the results of the compressive strength, it can be concluded that the added material is categorized as self-compacting concrete with high initial compressive strength, while at 28 days, the compressive strength test results are categorized as high-strength self-compacting concrete.

Details

World Journal of Engineering, vol. 17 no. 4
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 13 September 2021

Vijaya Prasad B., Arumairaj Paul Daniel, Anand N. and Siva Kumar Yadav

Concrete is a building material widely used for the infrastructural development. Cement is the binding material used for the development of concrete. It is the primary…

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Abstract

Purpose

Concrete is a building material widely used for the infrastructural development. Cement is the binding material used for the development of concrete. It is the primary cause of CO2 emission globally. The purpose of this study is to develop sustainable concrete material to satisfy the present need of construction sector. Geopolymer concrete (GPC) is a sustainable concrete developed without the use of cement. Therefore, investigations are being conducted to replace the cement by 100% with high calcium fly ash (FA) as binding material.

Design/methodology/approach

High calcium FA is used as cementitious binder, sodium hydroxide (NaOH) and sodium silicates (Na2SiO3) are used as alkaline liquids for developing the GPC. Mix proportions with different NaOH molarities of 4, 6, 8 and 10 M are considered to attain the appropriate mix. The method of curing adopted is ambient and oven curing. Workability, compressive strength and microstructure characteristics of GPC are analysed and presented.

Findings

An increase of NaOH in the mix decreases the workability. Compressive strength of 29 MPa is obtained for Mix-I with 8 M under ambient curing. A polynomial relationship is obtained to predict the compressive strength of GPC. Scanning electron microscope analysis is used to confirm the geo-polymerisation process in the microstructure of concrete.

Originality/value

This research work focuses on finding some alternative cementitious material for concrete that can replace ordinary portland cement (OPC) to overcome the CO2 emission owing to the utilisation of cement in the construction industry. An attempt has been made to use the waste material (high calcium FA) from thermal power plant for the production of GPC. GPC concrete is the novel building material and alternative to conventional concrete. It is the ecofriendly product contributing towards the improvement of the circular economy in the construction industry. There are several factors that affect the property of GPC such as type of binder material, molarity of activator solution and curing condition. The novelty of this work lies in the approach of using locally available high calcium FA along with manufactured sand for the development of GPC. As this approach is rarely investigated, to prove the attainment of compressive strength of GPC with high calcium FA, an attempt has been made during the present investigation. Other influencing parameter which affects the strength gain has also been analysed in this paper.

Details

Journal of Engineering, Design and Technology , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 30 August 2021

Jamal Khatib, Ali Jahami, Adel El Kordi, Mohammed Sonebi, Zeinab Malek, Rayan Elchamaa and Sarah Dakkour

The purpose of this paper is to concern with using municipal solid waste incineration bottom ash (MSWI-BA) in concrete application.

Abstract

Purpose

The purpose of this paper is to concern with using municipal solid waste incineration bottom ash (MSWI-BA) in concrete application.

Design/methodology/approach

In this paper, the performance of reinforced concrete (RC) beams containing MSWI-BA was investigated. Four concrete mixes were used in this study. The control mix had a proportion of 1 (cement): 2 (fine aggregates): 4 (coarse aggregates) by weight. In the other three mixes, the fine aggregates were partially replaced with 20%, 40% and 60% MSWI-BA (by weight). The water to cement ratio was kept constant at 0.5 in all mixes. Concrete cubes and cylinders were prepared to determine some physical and mechanical properties of concrete, whereas RC beams were used for determining the structural performance.

Findings

There was an increase in compressive strength, tensile strength and the modulus of elasticity when 20% of fine aggregates were replaced with MSWI-BA. However, beyond 20% these properties were reduced. The load bearing capacity and deflection were the highest for the control beam and the beam with 20% MSWI-BA.

Research limitations/implications

The research conducted in this investigation used a specific type of MSWI-BA. The composition of the waste can vary from one plant to another and this presents one of the limitations.

Practical implications

The findings of this research indicate that MSWI-BA can partially substitute fine aggregate, thus reducing the impact of construction on the environment.

Originality/value

The MSWI-BA used in this research differs from other types as the waste papers and cartons are removed from the waste and used to produce other products. Therefore, this study is considered original as it examines MSWI-BA with different properties for use in construction.

Details

Journal of Engineering, Design and Technology , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 7 March 2016

Zhiming Ma, Tiejun Zhao, Jianzhuang Xiao and Ting Guan

Rebar corrosion in reinforced concrete is the major reason for the durability degradation, especially under harsh environment. This paper presents an experiment conducted…

Abstract

Purpose

Rebar corrosion in reinforced concrete is the major reason for the durability degradation, especially under harsh environment. This paper presents an experiment conducted to investigate the influence of freeze-thaw cycles on the rebar corrosion in reinforced concrete. The purpose of this paper is to provide fundamental information about rebar corrosion under frost environment and improvement measures.

Design/methodology/approach

The related elastic modulus and compressive strength of different concrete specimens were measured after different freeze-thaw cycles. The accelerated rebar corrosion test was carried out after different freeze-thaw cycles; additionally, the value of calomel half-cell potential was determined. The actual rebar corrosion appearance was checked to prove the accuracy of the results of calomel half-cell potential.

Findings

The results show that frost damage aggravates the rebar corrosion rate and degree under freeze-thaw environment; furthermore, the results become more obvious with the freeze-thaw cycles increasing. Mixing the air-entrained agent into fresh concrete to prepare air-entrained concrete, increasing the cover thickness and processing the surface of concrete with a waterproofing agent can significantly improve the resistance to rebar corrosion. From the actual appearance of rebar corrosion, the results of calomel half-cell potential can well reflect the actual rebar corrosion in reinforced concrete.

Originality/value

The durability of reinforced concrete is mainly determined on chloride penetration that brings about rebar corrosion in chloride environments. Furthermore, the degradation of concrete durability becomes more serious in the harsh environment. As the concrete exposure to the freeze-thaw cycles environment, the freeze-thaw cycles accelerate the concrete damage, and the penetration of chloride into the concrete becomes easier because of the growing pore and crack sizes. In addition, rebar corrosion caused by chloride is one of the major forms of environmental attack on reinforced concrete. The tests conducted in this paper will describe the rebar corrosion in reinforced concrete under freeze-thaw environment.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 10 April 2007

Shibli R.M. Khan, J. Noorzaei, M.R.A. Kadir, A.M.T. Waleed and M.S. Jaafar

This paper aims to present a research finding that establishes a regression model between ultrasonic pulse velocity (UPV) tests and actual strength of high performance…

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Abstract

Purpose

This paper aims to present a research finding that establishes a regression model between ultrasonic pulse velocity (UPV) tests and actual strength of high performance concrete (HPC).

Design/methodology/approach

In this study, a total of 270 cube samples were made from six different mix proportions. The mixes were grouped in two series that consist of nominal maximum aggregate sizes of 10 mm (A10) and 19 mm (A19). Silica fume were used as mineral admixtures at 5 percent, 10 percent and 15 percent of cement in both series. UPV tests were conducted for each of the specimens, followed by destructive strength tests. The tests were carried out for concrete at different ages of between three to 56 days. The destructive test results were used as the true strength of the mixes and the UPV test results were used as strength estimation.

Findings

Concrete strength correlations between UPV and destructive tests were analysed for each mix proportions and in each series. These correlations are presented in the form of regression equations that displays standard error of between ±2.4 to ±5.7 MPa regardless of mix for the concrete in series A10. Similarly, in series A19 concrete, standard errors of between ±3.2 to ±6.7 MPa were found. Strength prediction models using UPV for high performance concrete are proposed. The models have overall correlation coefficients above 0.80 for all the mixes.

Originality/value

There are no standard relationships that had been established for high performance concrete strength with UPV test methods. The proposed relationship can be used for concrete strength estimation that is normally required in building or structural assessment, especially with the present trend of constructing modern structures using high performance concrete.

Details

Structural Survey, vol. 25 no. 1
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 1 January 1990

Roel van Es

Discusses the properties of concrete and the process of carbonationwhich can lead to corrosion and its ultimate destruction. Outlines theconditions which lead to…

Abstract

Discusses the properties of concrete and the process of carbonation which can lead to corrosion and its ultimate destruction. Outlines the conditions which lead to carbonation, detailing design faults which facilitate the process, and suggests preventatives which can protect the surface. Examines the results of carbonation, the forming of distressed concrete and mentions tests which can be performed to check the health of the structure. Assesses the impact of additional factors leading to corrosion and offers advice on remedial actions.

Details

Structural Survey, vol. 8 no. 1
Type: Research Article
ISSN: 0263-080X

Keywords

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