Influence of polypropylene fibres on the thermal and acoustic behaviour of untreated coal coarse aggregates concrete

2021 ◽  
Vol 36 ◽  
pp. 102125
Author(s):  
Arash Karimipour ◽  
Jorge de Brito ◽  
Mahmoud Edalati
Author(s):  
Ramaiah Prakash ◽  
Rajagopal Thenmozhi ◽  
Sudharshan N. Raman ◽  
Chidambaram Subramanian

The aim of this study is to investigate the effect of polypropylene fibre addition into eco-concrete made with fly ash, an industrial by product, as partial cement replacement material, and coconut shell, an agricultural waste,  as coarse aggregates, on the mechanical properties of the concrete. Two different mixes were developed, one with coconut shell only as coarse aggregates, and the other with the combination of both conventional aggregates and coconut shell as coarse aggregates. The cement content was replaced with class F fly ash at 10% by weight in the concrete mixes. The volume fractions of polypropylene fibres used in this study were 0.25%, 0.5%, 0.75% and 1.0%. The addition of polypropylene fibres slightly reduces the slump and density of coconut shell concrete. As the volume fraction of fibres increases, the compressive strength and modulus of elasticity of coconut shell concrete also increases by up to 0.5% of fibre volume fraction. The split tensile strength and flexural strength of coconut shell concrete were also enhanced with fibre addition. The addition of 0.75% and 1.0% volume fractions of polypropylene fibres slightly reduces compressive strength. Results of this study show that polypropylene fibres may be used in coconut shell concrete to improve the mechanical properties of the composite.


Author(s):  
Ionuţ Ştefan Iorgu ◽  
Alexandru Ioan Tatu ◽  
Elena Iulia Iorgu

Abstract During the period 2008-2012, the bush-cricket Isophya harzi Kis, 1960 has been the subject of several collecting trips in Cozia Mountains, where it was believed to be endemic, in order to study its acoustic behaviour. However, on a recent trip to Piatra Craiului Mountains, to study its Orthoptera fauna, I. harzi was surprisingly found in clearings and mountain steppe slopes covered with tall subalpine vegetation from Northern and Western areas. Bioacoustic analysis and some ecological notes are presented in the paper.


2021 ◽  
Vol 13 (10) ◽  
pp. 5741
Author(s):  
Muhammad Junaid Munir ◽  
Syed Minhaj Saleem Kazmi ◽  
Yu-Fei Wu ◽  
Xiaoshan Lin ◽  
Muhammad Riaz Ahmad

The addition of macro-polypropylene fibres improves the stress-strain performance of natural aggregate concrete (NAC). However, limited studies focus on the stress-strain performance of macro-polypropylene fibre-reinforced recycled aggregate concrete (RAC). Considering the variability of coarse recycled aggregates (CRA), more studies are needed to investigate the stress-strain performance of macro-polypropylene fibre-reinforced RAC. In this study, a new type of 48 mm long BarChip macro-polypropylene fibre with a continuously embossed surface texture is used to produce BarChip fibre-reinforced NAC (BFNAC) and RAC (BFRAC). The stress-strain performance of BFNAC and BFRAC is studied for varying dosages of BarChip fibres. Results show that the increase in energy dissipation capacity (i.e., area under the curve), peak stress, and peak strain of samples is observed with an increase in fibre dosage, indicating the positive effect of fibre addition on the stress-strain performance of concrete. The strength enhancement due to the addition of fibres is higher for BFRAC samples than BFNAC samples. The reduction in peak stress, ultimate strain, toughness and specific toughness of concrete samples due to the utilisation of CRA also reduces with the addition of fibres. Hence, the negative effect of CRA on the properties of concrete samples can be minimised by adding BarChip macro-polypropylene fibres. The applicability of the stress-strain model previously developed for macro-synthetic and steel fibre-reinforced NAC and RAC to BFNAC and BFRAC is also examined.


2021 ◽  
pp. 127011
Author(s):  
Yang Lu ◽  
Sihong Liu ◽  
Yonggan Zhang ◽  
Meng Yang ◽  
Zhongzhi Fu ◽  
...  
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Author(s):  
Muhammad Jaffar Memon ◽  
Ashfaque Ahmed Jhatial ◽  
Ali Murtaza ◽  
Muhammad Saleem Raza ◽  
Karim Bux Phulpoto

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