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Article
Publication date: 4 June 2021

Niragi Dave, Ramesh Guduru, Anil Kumar Misra and Anil Kumar Sharma

The consumption of supplementary cementitious materials (SCMs) has increased enormously in the construction industry. These SCMs are often waste materials or industrial…

Abstract

Purpose

The consumption of supplementary cementitious materials (SCMs) has increased enormously in the construction industry. These SCMs are often waste materials or industrial by-products. This study aims to investigate the bond strength using reinforcing bars in Normal Strength Concrete (M20 grade) and High Strength Concrete (M40 grade), developed using SCMs and data was compared with concrete prepared with ordinary portland cement (OPC). The findings of the study will help in reducing the dependency on OPC and promote the utilization of waste materials in Construction.

Design/methodology/approach

In the present study, the bond behavior between the steel bars and the concrete was investigated in controlled, binary and quaternary concretes of M20 and M40 grades. Following the conventional procedures, samples were prepared and mechanical tests conducted (as per IS:2770–1 code for M20 and M40 grade concrete structures), which showed an improvement in the bond strength depending on the extent of overall calcium and silica content in these composite mixtures, and thus reflected the importance of vigilant utilization of used industrial waste in the OPC as a replacement without exceeding silica content beyond certain percentages for enhanced structural properties.

Findings

Experimental evaluation of bond behavior results showed a brittle nature for the controlled (OPC) concrete mixtures. While binary and quaternary concrete was able to resist the load-carrying capacity under large deformations and prevented the split cracking and disintegration of the concretes. Among different variations in the chemistry, for both M20 and M40 grades, the maximum bond strengths were observed for 10% Metakaolin + 10% Silica Fume + 30% Fly Ash + 50% OPC composition and this could be attributed to the fineness of the additives, better packing and enhanced calcium silicate hydrate (C-S-H).

Originality/value

Quaternary concrete may be a future option in place of OPC concrete. Very limited data is available related to the bond strength of quaternary concrete. Experimental analysis on quaternary concrete shows that its use in construction can reduce both construction cost and a burden on natural raw materials used to make OPC.

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: 27 July 2021

Mervin Ealiyas Mathews, Anand N, Diana Andrushia A, Tattukolla Kiran and Khalifa Al-Jabri

Building elements that are damaged by fire are often strengthened by fiber wrapping techniques. Self-compacting concrete (SCC) is an advanced building material that is…

Abstract

Purpose

Building elements that are damaged by fire are often strengthened by fiber wrapping techniques. Self-compacting concrete (SCC) is an advanced building material that is widely used in construction due to its ability to flow and pass through congested reinforcement and fill the required areas easily without compaction. The aim of the research work is to examine the flexural behavior of SCC subjected to elevated temperature. This research work examines the effect of natural air cooling (AC) and water cooling (WC) on flexural behavior of M20, M30, M40 and M50 grade fire-affected retro-fitted SCC. The results of the investigation will enable the designers to choose the appropriate repair technique for improving the service life of structures.

Design/methodology/approach

In this study, an attempt has been made to evaluate the flexural behavior of fire exposed reinforced SCC beams retrofitted with laminates of carbon fiber reinforced polymer (CFRP), basalt fiber reinforced polymer (BFRP) and glass fiber reinforced polymer (GFRP). Beam specimens were cast with M20, M30, M40 and M50 grades of SCC and heated to 925ºC using an electrical furnace for 60 min duration following ISO 834 standard fire curve. The heated SCC beams were cooled by either natural air or water spraying.

Findings

The reduction in the ultimate load carrying capacity of heated beams was about 42% and 55% for M50 grade specimens that were cooled by air and water, respectively, in comparison with the reference specimens. The increase in the ultimate load was 54%, 38% and 27% for the specimens retrofitted with CFRP, BFRP and GFRP, respectively, compared with the fire-affected specimens cooled by natural air. Water-cooled specimens had shown higher level of damage than the air-cooled specimens. The specimens wrapped with carbon fiber could able to improve the flexural strength than basalt and glass fiber wrapping.

Originality/value

SCC, being a high performance concrete, is essential to evaluate the performance under fire conditions. This research work provides the flexural behavior and physical characteristics of SCC subjected to elevated temperature as per ISO rate of heating. In addition attempt has been made to enhance the flexural strength of fire-exposed SCC with wrapping using different fibers. The experimental data will enable the engineers to choose the appropriate material for retrofitting.

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: 20 February 2020

Daniel Paul Thanaraj, Anand N. and Prince Arulraj

The purpose of this study is to investigate the effect of standard fire on the strength and microstructure properties of concrete with different strength grades.

Abstract

Purpose

The purpose of this study is to investigate the effect of standard fire on the strength and microstructure properties of concrete with different strength grades.

Design/methodology/approach

Different strength grades of concrete used for the investigation are M20, M30, M40 and M50. An electrical bogie hearth furnace was developed to simulate the International Standards Organization 834 standard fire curve.Concrete samples were subjected to high temperatures of 925, 1,029, 1,090 and 1,133°C for the duration of 1, 2, 3 and 4 h, respectively, as per standard fire curve. Compressive strength, tensile strength, thermal crack pattern and spalling of heated concrete specimens were evaluated by experimental investigation. Scanning electron microscopy and thermo-gravimetric analysis were performed to investigate the microstructure properties of heated concrete specimens.

Findings

Test results indicated reduction in the strength and changes in the microstructure properties of concrete exposed to elevated temperature. The degree of weight and the strength loss were found to be higher for concrete with higher grades. An empirical relation is proposed to determine the residual strength of concrete with different strength grade using regression analysis.

Social implications

Results of this research will be useful for the design engineers to understand the behavior of concrete exposed to elevated temperature as per standard fire.

Originality/value

When concrete is exposed to elevated temperature, its internal microstructure changes, thereby strength and durability of concrete deteriorates. The performance of concrete with different strength grade exposed to standard fire is well understood. This research’s findings will be useful for the designers to understand more about fire resistance of concrete. A simple relationship is proposed to determine the residual strength of concrete exposed to various durations of heating.

Details

Journal of Structural Fire Engineering, vol. 11 no. 3
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 5 February 2021

Alwyn Varghese, Anand N., Diana Andrushia and Prince Arulraj

Aim of this research work is to examine the stress–strain behavior and modulus of elasticity of fiber-reinforced concrete (FRC) exposed to elevated temperature. The…

Abstract

Purpose

Aim of this research work is to examine the stress–strain behavior and modulus of elasticity of fiber-reinforced concrete (FRC) exposed to elevated temperature. The purpose of this paper is to study the effect of standard fire exposure on the mechanical and microstructure characteristics of concrete specimens with different strength grade.

Design/methodology/approach

An electrical bogie hearth furnace was developed to simulate the ISO 834 standard fire curve. Specimens were exposed to high temperatures of 821°C, 925°C and 986°C for the duration of 30, 60 and 90 min, respectively, as per standard fire curve. Peak stress, peak strain, modulus of elasticity and damage level of heated concrete specimens were evaluated by experimental investigation. SEM-based microstructure investigation has been carried out to analyze the microstructure characteristics of heated concrete specimens.

Findings

The results revealed that carbon fiber reinforced concrete was found to be better than the FRC made with other fibers on improving the modulus of elasticity of concrete. An empirical relationship has been established to predict the modulus of elasticity of temperature exposed specimens with different type of fiber and grade of concrete. In comparison with low melting point fibers, high melting point fibers exhibited higher modulus of elasticity under all tested conditions. Surface damage and porosity level of concrete with carbon and basalt fibers were found to be lower than other FRC.

Originality/value

Empirical relationship was developed to determine the modulus of elasticity of concrete exposed to elevate temperature, and this will be useful for concrete design applications. This research work may be useful for finding the residual compressive strength of concrete exposed to elevate temperature. So that it will be helpful to identify the suitable repair/retrofitting technique for reinforced concrete elements.

Details

World Journal of Engineering, vol. 18 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Content available
Article
Publication date: 27 July 2020

Nurul Shahnaz Mahdzan, Rozaimah Zainudin, Mohd Edil Abd Sukor, Fauzi Zainir and Wan Marhaini Wan Ahmad

The purpose of this paper is to empirically explore the financial well-being (FWB) of Malaysian households and to construct a subjective FWB index with present and future…

Abstract

Purpose

The purpose of this paper is to empirically explore the financial well-being (FWB) of Malaysian households and to construct a subjective FWB index with present and future time perspectives.

Design/methodology/approach

Data were collected from 1,867 respondents across five major regions in Malaysia. Adapting the InCharge Financial Distress/Financial Well-being (IFDFW) Scale by Prawitz et al. (2006) and the method of computing an index by Devlin (2009), this study develops an FWB index using subjective measures that include future time perspectives (retirement). The index was employed to measure the FWB across low-, middle- and high-income groups and socio-demographic characteristics.

Findings

This study finds evidence that Malaysians' FWB is at an average level (46.8). Middle-income households' FWB (46.1) flanks between the financial well-being index (FWBI) levels of the low-income (37.4) and high-income households (58.7). Across age groups, education levels and employment sectors, the FWB of Malaysians significantly varies, although not across different ethnics, religions, zones and residential areas. Overall, the results suggest that the detrimental effects of FWB are perceived by all Malaysian households nationwide regardless of their religion, ethnicity and residential areas.

Practical implications

The results of this study complement the other well-being indices used by policymakers and may serve as a useful input for government and policymakers for them to formulate appropriate strategies to promote higher FWB of Malaysian households based on their socio-demographic characteristics.

Originality/value

This study used primary data and developed a subjective FWB index that leverages on people's perceptions of their own financial well-being while including present and future time perspectives. The main contribution of this paper is to construct an index that is easily interpretable and that complements the existing FWB indices, and to identify the segments of society that have low vis-à-vis high FWB.

Details

Journal of Asian Business and Economic Studies, vol. 27 no. 3
Type: Research Article
ISSN: 2515-964X

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Article
Publication date: 11 January 2016

S Thirumal valavan, P. Malliga, P. Arulraj and G. Udayakumar

Automobiles have always been a major cause of air pollution. The vehicular emission contains several harmful pollutants that affect the surroundings and living beings…

Abstract

Purpose

Automobiles have always been a major cause of air pollution. The vehicular emission contains several harmful pollutants that affect the surroundings and living beings. Mild CO exposure leads to headaches or unconsciousness. CO is also responsible for the global warming as well. CO is mainly generated in the IC engine due to incomplete combustion of the fuel. The purpose of this paper is to implement a CO absorption mechanism inside the exhaust pipe of vehicle.

Design/methodology/approach

In this research work the single cylinder four stroke spark-ignition engine is intended to run on petroleum and petroleum blended fuels. A new post-combustion emission control device called cobalt scrubber is employed to reduce the emission of CO during idling which absorb and later release it under transient conditions.

Findings

The emission of CO when the engine runs at petroleum is reduced from 6.24 to 3.02 per cent. Methanol 40 per cent+petrol 60 per cent gives a better emission result of 0.98 per cent of CO emission. So, the authors can implement the cobalt scrubber in automobiles to avoid CO emission during idling.

Practical implications

The scrubber clearly overcomes the drawbacks of the existing control techniques. The cobalt scrubber is a cheap, non-radioactive. It can be employed in any kind of vehicle irrespective of its engine.

Originality/value

The use of the scrubber design presented in this article, effectively reduces the emission of CO.

Details

Management of Environmental Quality: An International Journal, vol. 27 no. 1
Type: Research Article
ISSN: 1477-7835

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Article
Publication date: 18 June 2021

Adithya Tantri, Gopinatha Nayak, Adithya Shenoy and Kiran K. Shetty

This study aims to present the results of an experimental evaluation of low (M30), mid (M40) and high (M50) grade self-compacting concrete (SCC) with three nominal maximum…

Abstract

Purpose

This study aims to present the results of an experimental evaluation of low (M30), mid (M40) and high (M50) grade self-compacting concrete (SCC) with three nominal maximum aggregate sizes (NMAS), namely, 20 mm, 16 mm and 12.5 mm, with Bailey gradation (BG) in comparison with Indian standard gradation (ISG).

Design/methodology/approach

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

Findings

Rheological and mechanical properties of SCC were evaluated in detail and according to the results, a concrete sample containing lower NMAS with BG demonstrated improvement in modulus of elasticity and compressive strength, while improving the rheological properties as well. Meanwhile, SCC demonstrated poor performance in split tensile and flexural strengths with lower NMAS gradations and a direct correlation was evident as the increase in NMAS caused an increase in the strength and vice-versa.

Originality/value

Upon comparison of BG with ISG, it was revealed that BG mixes succeeded to demonstrate superior performance. From the material optimization, rheological and mechanical performance study, it is recommended that BG with NMAS 16 mm can be used for conventional SCC.

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: 1 December 1982

READERS can be forgiven if they have thought, from time to time, that we are anti‐union. This is not true, although we admit to thinking that they have for a long time…

Abstract

READERS can be forgiven if they have thought, from time to time, that we are anti‐union. This is not true, although we admit to thinking that they have for a long time forgotten their prime reason for existence — to fight for human rights for their members against what were, in days long gone by, very inhuman employers.

Details

Work Study, vol. 31 no. 12
Type: Research Article
ISSN: 0043-8022

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Article
Publication date: 18 March 2014

N. Anand, G. Arulraj and C. Aravindhan

Development of Self Compacting Concrete (SCC) is considered as one of the most significant development in the construction industry due to its numerous inherited benefits…

Abstract

Development of Self Compacting Concrete (SCC) is considered as one of the most significant development in the construction industry due to its numerous inherited benefits. With the introduction of super-plasticizers and viscosity modifying agents, it is now possible to produce concrete with high fluidity, good cohesiveness which does not require external energy for compaction. The proper understanding of the effects of elevated temperatures on the properties of SCC is necessary to ensure the safety of buildings made with SCC during fire. During the present investigation, an attempt has been made to study the stress-strain behaviour of Normal Compacting Concrete (NCC) and Self Compacting Concrete at a temperature of 900°C. A significant reduction in the Ultimate compressive strength of SCC was observed during this study. The reduction was found to be more for SCC compared to Normal compacting concrete. The reduction in the compressive strength of SCC was found to be 81.5 % for M40 concrete when exposed to 900°C.

Details

Journal of Structural Fire Engineering, vol. 5 no. 1
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 17 July 2017

Hassan A.M. Mhamoud and Jia Yanmin

This study aims to investigate the effectiveness of different additives (individual effects) in improving the strength of concrete to resist temperatures of up to 60ºC.

Abstract

Purpose

This study aims to investigate the effectiveness of different additives (individual effects) in improving the strength of concrete to resist temperatures of up to 60ºC.

Design/methodology/approach

In all, 13 different mixtures with a constant water/binder ratio of 0.36 and grade M40 were prepared by using ordinary Portland concrete alone, or with partial replacement by fly ash (FA), blast-furnace slag, silica fume (SF) and a combination of all three. After 7 and 28 days under water, their strength and residual strength were measured.

Findings

The results of testing revealed that the addition of 10 per cent SF was found to result in the greatest increase in compressive strength and flexural strength along with decreased the residual strengths. The addition of FA increased the compressive strength and enhanced the residual compressive strength. However, it also decreased the residual flexural strength.

Originality/value

The addition of slag achieved better flexural strength and the best residual compressive strength. The combination of additives also enhanced the compressive strength but was not found to be better than using SF alone.

Details

Journal of Structural Fire Engineering, vol. 9 no. 2
Type: Research Article
ISSN: 2040-2317

Keywords

1 – 10 of 171