Effects of air-entraining agent and polypropylene fiber on the mechanical properties, autogenous shrinkage, and fracture properties of fully recycled aggregate concrete

Ding, Dong; Zhang, Lijuan; Zhao, Jun; Li, Changbin; Wang, Zhi

doi:10.3389/fmats.2022.1049304

Cited by 5 publications

(3 citation statements)

References 46 publications

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“…Besides surface tension, some studies argue that autogenous shrinkage is affected predominantly by the pore volume below 50 nm [37,38], where a higher pore volume would induce higher drying stress and therefore more shrinkage. Such a relationship was not observed for the copolymer samples of the current study.…”

Section: Autogenous Shrinkagementioning

confidence: 99%

Effect of Poly(ethylene glycol)–Poly(propylene glycol) Triblock Copolymers on Autogenous Shrinkage and Properties of Cement Pastes

Masoule,

Ghahremaninezhad

2024

Buildings

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This study investigates the hydration, microstructure, autogenous shrinkage, electrical resistivity, and mechanical properties of Portland cement pastes modified with PEG-PPG triblock copolymers with varied molecular weights. The early age properties including setting time and hydration heat were examined using the Vicat test and isothermal calorimetry. The hydration products and pore size distribution were analyzed using thermogravimetric analysis (TGA) and nitrogen adsorption, respectively. Mechanical properties and electrical resistivity were evaluated using the compressive strength test and electrochemical impedance spectroscopy (EIS). It was shown that the addition of the copolymers reduced the surface tension of the cement paste pore solution due to the presence of a hydrophobic block (PPG) in the molecular structure of the copolymers. The setting time and hydration heat were relatively similar in the control paste as well as the pastes modified with the copolymers. The results showed that copolymers were able to reduce the autogenous shrinkage in the paste due primarily to a reduction in pore solution surface tension. TGA showed a slight increase in the hydration degree of the paste modified with the copolymers. The compressive strength was reduced in the pastes modified with the copolymers that showed an increased volume of air voids. The addition of copolymers did not affect the electrical resistivity of the pastes except in the case where there was a large volume of air voids, which acted as electrical insulators.

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Section: Autogenous Shrinkagementioning

confidence: 99%

Effect of Poly(ethylene glycol)–Poly(propylene glycol) Triblock Copolymers on Autogenous Shrinkage and Properties of Cement Pastes

Masoule,

Ghahremaninezhad

2024

Buildings

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“…Currently, there is limited research on the effect of fiber on fully recycled concrete. Ding et al [ 28 ] reported that the incorporation of PF negatively affected the compressive strength and splitting tensile strength of fully recycled concrete but enhanced the flexural strength and fracture properties. Li et al [ 29 ] observed that basalt fiber improved the bonding performance in recycled aggregate, made the interface strength higher, and enhanced the shear failure of fully recycled concrete when the load grade reached 70%.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Fully Recycled Aggregate Concrete Reinforced with Steel Fiber and Polypropylene Fiber

Zhang,

Li,

et al. 2024

Materials

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The study and utilization of fully recycled aggregate concrete (FRAC), in which coarse and fine aggregates are completely replaced by recycled aggregates, are of great significance in improving the recycling rate of construction waste, reducing the carbon emission of construction materials, and alleviating the ecological degradation problems currently faced. In this paper, investigations were carried out to study the effects of steel fiber (0.5%, 1.0%, and 1.5%) and polypropylene fiber (0.9 kg/m3, 1.2 kg/m3 and 1.5 kg/m3) on the properties of FRAC, including compressive strength, splitting tensile strength, the splitting tensile load–displacement curve, the tensile toughness index, flexural strength, the load–deflection curve, and the flexural toughness index. The results show that the compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced FRAC were remarkably enhanced compared with those of ordinary FRAC, and the maximum increase was 56.9%, 113.3%, and 217.0%, respectively. Overall, the enhancement effect of hybrid steel–polypropylene fiber is more significant than single-mixed fiber. Moreover, the enhancement of the crack resistance, tensile toughness, and flexural toughness obtained by adding steel fiber to the FRAC is more significant than that obtained by adding polypropylene fiber. Furthermore, adding polypropylene fiber alone and mixing it with steel fiber showed different FRAC splitting tensile and flexural properties.

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“…Also, BF enhance the tensile and flexural capacities of the cementitious composites that can reduce and delay the cracking caused by shrinkage, thermal variations, and chemical attacks. Polypropylene (PP) fibres have also previously been found beneficial in reducing the shrinkage, thermal cracks, and improving durability 24 , 25 . Therefore, the hybridization of PP fibres with BF can offer desirable characteristics to cementitious composites while ensuring sustainability.…”

Section: Introductionmentioning

confidence: 99%

Effects of aircraft operating fluids and environmental thermal fatigue on fly ash and steel slag based cementitious composites

Tangirala,

Rawat,

Lahoti

2024

Sci Rep

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This paper investigates the performance of concrete incorporating high-volume fly ash (HVFA) and steel slag aggregates against the detrimental effects of combined cycles of environmental thermal fatigue and exposure to leaked aircraft fluids. A total of 128 cubes and 90 prisms were cast for five mixes and exposed to 60, 120, 180, 240 and 300 combined cycles. The results demonstrate the positive effect of utilization of HVFA which reduces the total amount of portlandite available in the system. The SS aggregates demonstrate a strong interlocking with the surrounding matrix and supply the necessary portlandite for continued pozzolanic reaction. However, their reaction with aircraft fluids causes significant degradation to flexural strength initially, which is redeemed by pozzolanic reaction at a later stage. Hybrid basalt and polypropylene fibres were successful in enhancing the flexural strength and reducing the cracking. The mercury intrusion porosimetry revealed a reduction in pore volume because of HVFA. Scanning electron microscopy and differential scanning calorimetry were also employed to uncover the underlying mechanisms of damage and assess the performance of the cementitious composite.

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Effects of air-entraining agent and polypropylene fiber on the mechanical properties, autogenous shrinkage, and fracture properties of fully recycled aggregate concrete

Cited by 5 publications

References 46 publications

Effect of Poly(ethylene glycol)–Poly(propylene glycol) Triblock Copolymers on Autogenous Shrinkage and Properties of Cement Pastes

Effect of Poly(ethylene glycol)–Poly(propylene glycol) Triblock Copolymers on Autogenous Shrinkage and Properties of Cement Pastes

Mechanical Properties of Fully Recycled Aggregate Concrete Reinforced with Steel Fiber and Polypropylene Fiber

Effects of aircraft operating fluids and environmental thermal fatigue on fly ash and steel slag based cementitious composites

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