Manjeet Jassal, Ashwini K. Agrawal, Arnab K. Ghosh, K.R.T. Ramasubramani and Anasuya Sahoo
Polymeric fibres that have a unique capability to change their structure in response to small environmental changes such as pH, electrolyte and electric field are an attractive…
Abstract
Polymeric fibres that have a unique capability to change their structure in response to small environmental changes such as pH, electrolyte and electric field are an attractive alternative for artificial muscles. Stimuli sensitive fibres were prepared by the modification of commercial polyacrylonitrile (PAN) fibres. The modification was carried out in two steps: thermo-oxidation and hydrolysis. During the thermo-oxidation step, the crosslinks imparted through the pendant nitrile groups provided a stable structure. While in the subsequent saponification step, the uncrosslinked nitrile groups were converted to responsive carboxylic acid groups. The effect of stabilization parameters and saponification conditions on the structure, properties and swelling behaviour of these fibres was investigated. The fibres showed muscle like expanding and contracting behaviour stimulated by changes in pH of the environment.
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Shoaib Ahmad and Ghulamul Hasnain
Steel fibers reinforced concrete (SFRC) is now widely accepted as a construction material for its added benefits. The proven increases in high shear capacity, toughness, bridging…
Abstract
Purpose
Steel fibers reinforced concrete (SFRC) is now widely accepted as a construction material for its added benefits. The proven increases in high shear capacity, toughness, bridging action of fibers and bond improvement from addition of steel fibers into mix design is a field yet to be explored, Therefore, Reinforced Cement Concrete (RCC) beam-column joint with steel fibers was modeled and analyzed for cyclic loading.
Design/methodology/approach
Beam-column joint is the most critical section of a structure under mixed loading such as that during a seismic episode. Therefore, in this research a reinforced SFRC beam column joint is modeled and analyzed for cyclic earthquake loading with the help of finite element analysis (FEA) software ABAQUS to compare the results with the experimental study.
Findings
Nonlinear static and nonlinear dynamic analysis are carried out on the SFRC joint for the comparison of simulated results with the experimental analysis.
Originality/value
In this paper, Initially, modeling of SFRC joint was done. Then, the finite element analysis of beam-column joint with steel fibers was carried out. After number of simulations, obtained FEA results were compared with the experimental work on the based on the load vs deflection curve, shear stresses, plastic strain region and plastic strain pattern. After the comparison, it was found that the performance of the numeric model for cyclic loading verified the experimental study, and the results obtained were quite promising.
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Emel Ken D. Benito, Ariel Miguel M. Aragoncillo, Kylyn A. Morales, Dalisa Mars L. Revilleza, Laurence V. Catindig and Marish S. Madlangbayan
Using coconut shell aggregates (CSA) in concrete benefits agricultural waste management and reduces the demand for mineral resources. Several studies have found that concrete…
Abstract
Purpose
Using coconut shell aggregates (CSA) in concrete benefits agricultural waste management and reduces the demand for mineral resources. Several studies have found that concrete containing CSA can achieve strengths that are comparable to regular concrete. The purpose of the present work is to evaluate the concrete’s durability-related properties to supplement these earlier findings.
Design/methodology/approach
Cylindrical specimens were prepared with a constant water–cement ratio of 0.50 and CSA content ranging from 0% to 50% (at 10% increment) by volume of the total coarse aggregates. The specimens were cured for 28 days and then tested for density, surface hardness, electrical resistivity and water sorptivity. The surface hardness was measured to describe the concrete resistance to surface wearing, while the resistivity and sorptivity were evaluated to describe the material’s resistance to fluid penetration.
Findings
The results showed that the surface hardness of concrete remained on average at 325 Leeb and did not change significantly with CSA addition. The distribution of surface hardness was also similar across all CSA groups, with the interquartile range averaging 59 Leeb. These results suggest that the cement paste and gravel stiffness had a more pronounced influence on the surface hardness than CSA. On the other hand, concrete became lighter by about 9%, had lower resistivity by 80% and had significantly higher initial sorptivity by up to 110%, when 50% of its natural gravel was replaced with CSA. Future work may be done to improve the durability of CSA when used as coarse aggregate.
Originality/value
The present study is the first to show the lack of correlation between CSA content and surface hardness. It would mean that the surface hardness test may not completely capture the porous nature of CSA-added concrete. The paper concludes that without additional treatment prior to mixing, CSA may be limited only to applications where concrete is not in constant contact with water or deleterious substances.