Evaluation of the mechanical properties, durability and drying shrinkage of the mortar reinforced with polyacrylonitrile microfibers

Chinchillas-Chinchillas, Manuel J.; Orozco-Carmona, Víctor M.; Gaxiola, Alberto; Alvarado-Beltrán, Clemente G.; Pellegrini-Cervantes, Manuel J.; Baldenebro-López, F.J.; Castro-Beltrán, A.

doi:10.1016/j.conbuildmat.2019.03.178

Cited by 30 publications

(15 citation statements)

References 55 publications

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“…Nowadays several alternatives that allow a reduction in the porosity percentage in concrete have been established, such as the inclusion of additives, the setting of low w/c ratios, the inclusion of fibers or the application of pozzolans [19,20]. Regarding the last alternative, SF is the most used pozzolan for improving the properties of concrete and reducing the porosity [21] when the ITZ is densified; this can react with the cement hydration products (calcium hydroxide—CH–) to form calcium silicate hydrate (CSH), which thereby improves the mechanical strength.…”

Section: Introductionmentioning

confidence: 99%

SEM Image Analysis in Permeable Recycled Concretes with Silica Fume. A Quantitative Comparison of Porosity and the ITZ

Chinchillas-Chinchillas

Rosas-Casarez

Arredondo-Rea

et al. 2019

Materials

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Recycled aggregates (RA) from construction and demolition can be used in permeable concretes (PC), improving the environment. PCs have a significant porous network, their cement paste and the interaction between the paste and the RA establishing their strength. Therefore, it is important to evaluate the porosity in the interfacial transition zones. The porosity of the cement paste, the aggregate and the interfacial transitional zones (ITZ) of a PC with recycled coarse aggregates (RCA) and silica fume (SF) is measured by means of image analysis–scanning electron microscope (IA)-(SEM) and by mapping the chemical elements with an SEM-EDS (energy dispersive spectrometer) detector microanalysis linked to the SEM and, as a contrast, the mercury intrusion porosimetry technique (MIP). In the IA process, a “mask” was created for the aggregate and another for the paste, which determined the porosity percentage (for the anhydrous material and the products of hydration). The results showed that using SF caused a reduction (32%) in the cement paste porosity in comparison with the PC with RA. The use of RA in the PC led to a significant increase (190%) in the porosity at different thicknesses of ITZ compared with the reference PC. Finally, the MIP study shows that the use of SF caused a decrease in the micropores, mesopores and macropores.

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Section: Introductionmentioning

confidence: 99%

SEM Image Analysis in Permeable Recycled Concretes with Silica Fume. A Quantitative Comparison of Porosity and the ITZ

Chinchillas-Chinchillas

Rosas-Casarez

Arredondo-Rea

et al. 2019

Materials

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“…Compared with the control mortar, the apparent porosity of P1, P2, P3, and P4 decreased by 1.44%, 2.65%, 3.20%, and 4.74%, respectively, at 28 d. Different authors attribute the decrease in porosities of mortar to the filling effect of the microfibers. e higher the addition of PPF, the lower the porosity, because the internal pores (due to the filling effect) and the capillary pores (generated by the evaporation of water) are reduced [46]. Compared with the control group, the water absorption of P1, P2, P3, and P4 groups decreased by 1.48%, 2.94%, 4.49%, and 5.34%, respectively, at 28 d. e low water absorption values can be attributed to the decrease in porosity.…”

Section: Physical Propertiesmentioning

confidence: 99%

“…e increase of compressive strength can be attributed to the ability of PPF to interrupt the initiation of microcracks, deviate their direction or avoid the extension of cracks, absorb tensions, decrease porosity, etc. [46,64,65]. Figure 7 shows the drying shrinkage of all mixtures over the recording period of 56 days.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…Recently, researchers have shown an increased interest in filling fibers (steel fiber, basalt fiber, glass fiber, carbon fiber, polyacrylonitrile fiber, polypropylene fiber, etc.) into OPC mortar or concrete to reduce the shrinkage deformation and have made a lot of progress [44][45][46]. Similarly, adding fibers into AAS mortar can effectively reduce its shrinkage deformation.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Polypropylene Fiber on Properties of Alkali-Activated Slag Mortar

Chen

Wang

2020

Advances in Civil Engineering

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Alkali-activated slag (AAS) is becoming an increasingly popular building material due to its excellent engineering properties and low CO 2 emissions, but its large shrinkage is an important reason to restrict its application and popularization. is work is aimed to study the possibility of inhibiting the shrinkage of AAS mortar by incorporating polypropylene fiber (PPF). For this, an experimental study was carried out to evaluate the effects of PPF content on setting time, fluidity, physical properties, mechanical properties, impact resistance, and microstructure of AAS mortar. e volume content of PPF is 0.05%, 0.1%, 0.15%, and 0.2%. e working, physical (porosity, water absorption, and bulk density), mechanical, shrinkage, and impact resistance properties of the AAS mortars were evaluated. e results show that incorporating PPF effectively reduces the shrinkage deformation of AAS mortar, significantly improves its impact resistance, enhances its toughness, and slightly improves its compressive strength in the later stage. At the same time, PPF delays the initial setting time of AAS mortar and reduces the fluidity, density, porosity, and water absorption of AAS mortar. SEM results show that the bridging effect of PPF between AAS mortars can inhibit the generation and propagation of cracks, improve the internal microstructure, and enhance the performance of AAS mortar.

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“…Steel fibers are very expensive and produce corrosion [29], glass fibers are very fragile and do not transmit elasticity to the mortar, [30], therefore, polymer fibers are the best option, they are produced at a low cost, they have high elastic properties and they are easy to place in the mortar mixture, improving its dispersion [31], in addition to being the least studied in the construction engineering area. Some of the fibers used as reinforcement of cementitious materials are polypropylene fibers [32], polyethylene terephthalate (PET) fibers [33], polyvinyl alcohol (PVA) fibers [34], among others, but few studies have been done with polyacrylonitrile (PAN) reinforcing fibers [35]. PAN is a polymer widely used in the industry, and has been widely used for the synthesis of microfibers because it has good mechanical properties, easy spinning, chemical stability and high durability [36].…”

Section: Introductionmentioning

confidence: 99%

Properties of Mortar with Recycled Aggregates, and Polyacrylonitrile Microfibers Synthesized by Electrospinning

Chinchillas-Chinchillas

Pellegrini-Cervantes

Castro-Beltrán

et al. 2019

Materials

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Currently it is necessary to find alternatives towards a sustainable construction, in order to optimize the management of natural resources. Thus, using recycled fine aggregate (RFA) is a viable recycling option for the production of new cementitious materials. In addition, the use of polymeric microfibers would cause an increase in the properties of these materials. In this work, mortars were studied with 25% of RFA and an addition of polyacrylonitrile PAN microfibers of 0.05% in cement weight. The microfibers were obtained by the electrospinning method, which had an average diameter of 1.024 µm and were separated by means of a homogenizer to be added to the mortar. Cementing materials under study were evaluated for compressive strength, flexural strength, total porosity, effective porosity and capillary absorption, resistance to water penetration, sorptivity and carbonation. The results showed that using 25% of RFA causes decreases mechanical properties and durability, but adding PAN microfibers in 0.05% caused an increase of 2.9% and 30.8% of compressive strength and flexural strength respectively (with respect to the reference sample); a decrease in total porosity of 5.8% and effective porosity of 7.4%; and significant decreases in capillary absorption (approximately 23.3%), resistance to water penetration (25%) and carbonation (14.3% after 28 days of exposure). The results showed that the use of PAN microfibers in recycled mortars allowed it to increase the mechanical properties (because they increase the tensile strength), helped to fill pores or cavities and this causes them to be mortars with greater durability. Therefore, the use of PAN microfibers as a reinforcement in recycled cementitious materials would be a viable option to increase their applications.

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Evaluation of the mechanical properties, durability and drying shrinkage of the mortar reinforced with polyacrylonitrile microfibers

Cited by 30 publications

References 55 publications

SEM Image Analysis in Permeable Recycled Concretes with Silica Fume. A Quantitative Comparison of Porosity and the ITZ

SEM Image Analysis in Permeable Recycled Concretes with Silica Fume. A Quantitative Comparison of Porosity and the ITZ

Effect of Polypropylene Fiber on Properties of Alkali-Activated Slag Mortar

Properties of Mortar with Recycled Aggregates, and Polyacrylonitrile Microfibers Synthesized by Electrospinning

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