scholarly journals Behaviour of Cementitious Composites Reinforced with Polypropylene Fibres using Restrained Eccentric Ring Test

Author(s):  
M.A. Abusogi ◽  
Mudthir Bakri
2020 ◽  
Vol 322 ◽  
pp. 01028
Author(s):  
Wojciech Szymkuć ◽  
Piotr Tokłowicz

The paper presents the results of experimental investigation of lightweight cementitious composites with cenospheres (LCCC) exposed to high temperatures. We showed the positive effect of cenospheres on post- fire residual compressive strength in previous papers. This paper focuses on the LCCC with the addition of polypropylene (PP) fibres. Specimens are heated up to 400, 600, 800, 1000 and 1200 °C. Then they are cooled to ambient temperature and their residual flexural and compressive strength is tested. The results are compared with non-heated specimens with compressive strength above 50 MPa. For plain LCCC composites, the results show significant improvement of residual compressive strength in comparison with typical concretes. No significant changes of compressive strength are found after exposure to temperatures up to 600°C – more than 85 % of the residual compressive strength is retained after exposure to this temperature for both mixes. Polypropylene fibres are found to be a successful mean to mitigate spalling without significantly lowering neither ambient nor residual compressive strength. Moreover, designed composite has low density and low thermal conductivity at room temperature.


This study focuses on assessing the durability property of engineered cementitious composites using Ultrasonic pulse velocity method (direct and semi direct) to compute the compressive strength. Even the effect of mineral admixture on the mortar properties for different curing regimes shall be determined using this method. Mortar specimens containing microsilica in different percentages ranging from 5% to 25%, replacing portland cement by weight and adding polypropylene fibres ranging from 0.5% to 2% are chosen for evaluation. 20% of microsilica and 2% of polypropylene fibres induced to increase the range of UPV from 3463 m/s to 3505 m/s for 7 and 28 day curing regimes and also the compressive strength significantly improved for the above constituent. However there was a marginal decrease in the compressive strength and UPV outcomes when cement is replaced by microsilica greater than 20%. A relationship had been framed between ultrasound pulse velocity and compressive strength.


2017 ◽  
Vol 737 ◽  
pp. 471-476
Author(s):  
Lukáš Zvolánek ◽  
Ivailo Terzijski

This paper focuses on the calculation of residual stresses due to shrinkage with a tensile creep effect. Whereas the shrinkage of concrete causes stresses in the material, the tensile creep counteracts the shrinkage as a stress relaxation mechanism. The main objective of this paper is to evaluate the ageing coefficient c (referred to as Trost-Bazant Coefficient) reflecting the load history. The coefficient is used for the residual stress analysis by means of a simplified method called Age-adjusted Effective Modulus Method. The tensile creep effect was evaluated according to the rheological model provided by Eurocode 2. Although the Eurocode predicts the creep for the structural members subjected to compressive stresses, this study proves that it can be used for the tensile creep prediction as well. We tested three types of concrete: reference concrete, high-performance concrete with reduced shrinkage magnitude by means of special admixtures, and fibre concrete with the content of polypropylene fibres. From the obtained results, it can be stated, that the ageing coefficient can be considered to be the value of 0.45 for any shrinkage development. It was also proved, that the tensile creep value essentially affects the magnitude of residual stresses, even in the “early age” concrete. The correctness of the calculated residual stresses was verified by means of a Ring-test.


2013 ◽  
Vol 464 ◽  
pp. 25-30 ◽  
Author(s):  
Daniel Kopkáně ◽  
Lenka Bodnárová ◽  
Rudolf Hela

The paper refers to utilization of low temperature plasma discharge in air on polypropylene fibres. Such fibres have been tested in concrete as reinforcement. The effect has been tested by restrain ring test. The experiment proved positive correlation between time of exposure and cracks suppression. The effect is considered as improved cohesion of polymer fibres with cement matrix.


2020 ◽  
Vol 72 (6) ◽  
pp. 314-322
Author(s):  
Jianwen Shao ◽  
Han Zhu ◽  
Bin Rong ◽  
Hongliang Li ◽  
Ziheng Yang

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