The properties of the cement screeds with the addition of polypropylene fibres and the shrinkage-reducing admixture

The results of a laboratory investigation on the early autogenous shrinkage of high strength concrete, and the possibilities of its reduction, are presented. Such concrete demonstrates significant autogenous shrinkage, which should, however, be limited in the early stages of its development in order to prevent the occurrence of cracks and/or drop in the load-carrying capacity of concrete structures. The following possibilities for reducing autogenous shrinkage were investigated: the use of low-heat cement, a shrinkage-reducing admixture, steel fibres, premoistened polypropylene fibres, and presoaked lightweight aggregate. In the case of the use of presoaked natural lightweight aggregate, with a fraction from 2 to 4 mm, the early autogenous shrinkage of one-day-old high strength concrete decreased by about 90%, with no change to the concrete's compressive strength in comparison with that of the reference concrete.

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Axial Stress-Strain Performance of Recycled Aggregate Concrete Reinforced with Macro-Polypropylene Fibres

Sustainability ◽

10.3390/su13105741 ◽

2021 ◽

Vol 13 (10) ◽

pp. 5741

Author(s):

Muhammad Junaid Munir ◽

Syed Minhaj Saleem Kazmi ◽

Yu-Fei Wu ◽

Xiaoshan Lin ◽

Muhammad Riaz Ahmad

Keyword(s):

Axial Stress ◽

Peak Stress ◽

Polypropylene Fibre ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Peak Strain ◽

Stress Strain ◽

Polypropylene Fibres ◽

Aggregate Concrete

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.

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Correction to: Production of eco-friendly concrete incorporating rice husk ash and polypropylene fibres

Environmental Science and Pollution Research ◽

10.1007/s11356-021-13750-8 ◽

2021 ◽

Author(s):

Muhammad Jaffar Memon ◽

Ashfaque Ahmed Jhatial ◽

Ali Murtaza ◽

Muhammad Saleem Raza ◽

Karim Bux Phulpoto

Keyword(s):

Rice Husk ◽

Rice Husk Ash ◽

Polypropylene Fibres

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

Journal of Building Engineering ◽

10.1016/j.jobe.2020.102125 ◽

2021 ◽

Vol 36 ◽

pp. 102125

Author(s):

Arash Karimipour ◽

Jorge de Brito ◽

Mahmoud Edalati

Keyword(s):

Polypropylene Fibres ◽

Acoustic Behaviour ◽

Coarse Aggregates

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Sustainable Use of Waste Polypropylene Fibres to Enhance the Abrasion and Skid Resistance of Two-Stage Concrete

Sustainability ◽

10.3390/su13095200 ◽

2021 ◽

Vol 13 (9) ◽

pp. 5200

Author(s):

Rayed Alyousef

Keyword(s):

Abrasion Resistance ◽

Research Work ◽

Sustainable Use ◽

Plain Concrete ◽

Skid Resistance ◽

Two Stage ◽

Polypropylene Fibres ◽

Conventional Concrete ◽

Carpet Industry ◽

Waste Polypropylene

Two-stage concrete (TSC), also known as prepacked aggregate concrete (PAC), differs from traditional concrete in terms of site application and manufacturing process. Although this type of concrete is not a replacement for conventional concrete applications, it is an ideal option for unusual and difficult placing conditions, especially for repairing existing concrete structures. In other words, this type of concrete is a newly developed concrete and made by placing and packing coarse aggregates and fibres in a designed formwork, then injecting a cement grout mixture into the free spaces between the aggregate particles using gravity or a pump device. For the mentioned system and others, concrete components used as floors or pavements must have an adequate degree of roughness during service life when exposed to skid and abrasion. Thus, this research work introduced a new concrete method (prepacked aggregates fibre-reinforced concrete—PAFRC) with high abrasion and skid resistance reinforced with waste polypropylene (PP) fibres from the carpet industry. The effects of PP fibres at 0–1% dosages on the mechanical properties, abrasion resistance, and skid resistance of PAFRC mixes were studied. The results revealed that the addition of PP fibres reduces the compressive strength of concrete mixtures. Nonetheless, the presence of PP fibres results in PAFRC mixes having higher tensile strength, abrasion resistance, and skid resistance than plain concrete. It was detected that in both grouting methods (gravity and pump), with the addition of PP fibre up to a specific dosage, the resistance against abrasion and skid was increased by about 26% compared to plain PAC mix. Additionally, the outcomes indicated that PAFRC is a promising material for applications such as pavements with high abrasion and skid resistance.

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Polypropylene Fibre Reinforced Concrete Air Permeability

MRS Proceedings ◽

10.1557/proc-211-71 ◽

1990 ◽

Vol 211 ◽

Cited By ~ 2

Author(s):

Miguel A. Sanjuan ◽

A. Moragues ◽

B. Bacle ◽

C. Andrade

Keyword(s):

Carbon Dioxide ◽

Reinforced Concrete ◽

Steel Corrosion ◽

Air Permeability ◽

Polypropylene Fibre ◽

Fibre Reinforced Concrete ◽

Polypropylene Fibres ◽

Cement Ratio ◽

Reinforcing Steel Corrosion

AbstractThe permeability of concrete to gases is of direct importance to the durability of concrete structures, because of carbon dioxide flowing through the concrete favour lime carbonation and reinforcing steel corrosion.Mortar with and without polypropylene fibres having water/cementitious ratios of 0.30, 0.35 and 0.40 and a cement/sand ratio of 1/1 were studied. Polypropylene dosage varied from 0.1 to 0.3% by volume of cement.The characterization of mortar permeability was made using cylindrical shaped samples (3 cm height and 15 cm diameter). These specimens were 28 days cured and then dried before the test.The addition of fibres results in a decrease of air permeability. Variation of the water/cement ratio is of lesser importance than fiber addition.

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