scholarly journals Influence of micro polypropylene fibres on the fracture energy and mechanical characteristics of recycled coarse brick aggregate concrete

2022 ◽  
Vol 314 ◽  
pp. 125667
Author(s):  
Arash Karimipour
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.


2018 ◽  
Vol 5 (1) ◽  
pp. 1147-1155 ◽  
Author(s):  
BM. Hanumesh ◽  
BA. Harish ◽  
N. Venkata Ramana

2017 ◽  
Vol 149 ◽  
pp. 669-678 ◽  
Author(s):  
Alper Bideci ◽  
Hakan Öztürk ◽  
Özlem Salli Bideci ◽  
Mehmet Emiroğlu

2013 ◽  
Vol 19 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Audrius Grinys ◽  
Henrikas Sivilevičius ◽  
Darius Pupeikis ◽  
Ernestas Ivanauskas

Every year, colossal amounts of used and non-biodegradable rubber tyres are accumulated in the world. Experience shows that the most efficient way to increase the concrete fracture energy G F (N/m) is to use metal or polypropylene fibres. The optimal content of fibre increases concrete resistance to stress (especially tensile stress under bending force). Concrete fracture is not brittle; concrete continues deforming after maximum stresses and is able to resist certain stresses, there is no abrupt decrease in loading. The research has proved that crumb rubber can be used in concretes as an alternative to metal and polypropylene fibres. The investigation has found that rubber waste additives, through their specific properties can partly take up tensile stresses in concrete and make the concrete fracture more plastic; besides, such concrete requires a significantly higher fracture energy and concrete samples can withstand much higher residual strength at 500 µm crack mouth opening displacement (CMOD) and deflection.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Gai-Fei Peng ◽  
Yan-Zhu Huang ◽  
Hai-Sheng Wang ◽  
Jiu-Feng Zhang ◽  
Qi-Bing Liu

This paper presents an experimental research on mechanical properties of recycled aggregate concrete (RAC) at low and high water/binder (W/B) ratios. Concrete at two W/B ratios (0.255 and 0.586) was broken into recycled concrete aggregates (RCA). A type of thermal treatment was employed to remove mortar attached to RCA. The RAC at a certain (low or high) W/B ratio was prepared with RCA made from demolished concrete of the same W/B ratio. Tests were conducted on aggregate to measure water absorption and crushing values and on both RAC and natural aggregate concrete (NAC) to measure compressive strength, tensile splitting strength, and fracture energy. The mechanical properties of RAC were lower than those of NAC at an identical mix proportion. Moreover, the heating process caused a decrease in compressive strength and fracture energy in the case of low W/B ratio but caused an increase in those properties in the case of high W/B ratio. The main type of flaw in RCA from concrete at a low W/B ratio should be microcracks in gravel, and the main type of flaw in RCA from concrete at a high W/B ratio should be attached mortar.


Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2678 ◽  
Author(s):  
Jin Young Yoon ◽  
Hyunjun Kim ◽  
Young-Joo Lee ◽  
Sung-Han Sim

The mechanical properties of lightweight aggregate concrete (LWAC) depend on the mixing ratio of its binders, normal weight aggregate (NWA), and lightweight aggregate (LWA). To characterize the relation between various concrete components and the mechanical characteristics of LWAC, extensive studies have been conducted, proposing empirical equations using regression models based on their experimental results. However, these results obtained from laboratory experiments do not provide consistent prediction accuracy due to the complicated relation between materials and mix proportions, and a general prediction model is needed, considering several mix proportions and concrete constituents. This study adopts the artificial neural network (ANN) for modeling the complex and nonlinear relation between constituents and the resulting compressive strength and elastic modulus of LWAC. To construct a database for the ANN model, a vast amount of detailed and extensive data was collected from the literature including various mix proportions, material properties, and mechanical characteristics of concrete. The optimal ANN architecture is determined to enhance prediction accuracy in terms of the numbers of hidden layers and neurons. Using this database and the optimal ANN model, the performance of the ANN-based prediction model is evaluated in terms of the compressive strength and elastic modulus of LWAC. Furthermore, these prediction accuracies are compared to the results of previous ANN-based analyses, as well as those obtained from the commonly used linear and nonlinear regression models.


2019 ◽  
Vol 969 ◽  
pp. 80-85 ◽  
Author(s):  
Anand Raj ◽  
Arshad P.J. Usman ◽  
Praveen Nagarajan ◽  
A.P. Shashikala

Fracture energy (Gf) studies provide us with means to assess the variation in ductility of concrete. This paper presents the results of fracture energy studies conducted on 18 mixes of M60 Grade concrete consisting of rubcrete (0%, 5%, 10%, 15% of crumb rubber), steel fibre reinforced rubcrete (0.25%, 0.5%, 0.75%, 1% steel fibres and 0% and 15% crumb rubber) and polypropylene fibre reinforced rubcrete (0.1%, 0.2%, 0.3% polypropylene fibres and 0% and 15% crumb rubber) using three-point bend beam tests on 60 × 100 × 500 mm specimens as per TC 50 FMC (1985). Results indicated an enhancement of fracture energy with an increase in rubber content.


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