Mineralogical and microstructural changes promoted by accelerated carbonation and ageing cycles of hybrid fiber–cement composites

Pizzol, Vinnicius Dordenoni; Mendes, Lourival Marin; Savastano, Holmer; Frías, Moisés; Dávila, Felipe Jaime; Cincotto, Maria Alba; John, Vanderley M.; Tonoli, Gustavo Henrique Denzin

doi:10.1016/j.conbuildmat.2014.06.055

Cited by 64 publications

(51 citation statements)

References 28 publications

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“…These findings are consistent with reports by Pizzol et al [43] for hybrid fibre cement composites exposed to accelerated carbonation for 10 h at 60 °C and 90% RH, in which no crystalline ettringite, monosulfate or monocarboaluminate was identified in the carbonated composite. The present findings show that the addition of 20% ACW to OPC hastens carbonation.…”

Section: Xrd and Sem Findingssupporting

confidence: 83%

Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties

et al. 2018

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Abstract:The worldwide pursuit of new eco-efficient pozzolans is ongoing. Kaolinite-based waste is an eco-friendly source of recycled metakaolinite, a highly pozzolanic product. In this study, a blended cement paste containing 20% activated coal waste (ACW) was exposed to a 100% CO 2 atmosphere at 65% RH for 7 days. The variations in its phase composition and strength were studied and compared to an OPC control. Both pastes were cured for 28 days prior to the carbonation test. Reaction kinetics were assessed using XRD, SEM/EDX, TG/DTG, FT-IR, Micro-Raman spectroscopy, pore solution pH and the cumulative carbonated fraction. The blended cement carbonated 68% faster than the control. While portlandite carbonation was the main reaction in both cements, decalcification was also observed (more intensely in the 20% ACW paste) in other hydraulic calcium phases (C-S-H gel, monocarboaluminate (C 4 AcH 12 ), ettringite and tetracalcium aluminate (C 4 AH 13 ). The end product of this reaction was calcium carbonate, mainly in the form of calcite, although traces of aragonite and amorphous carbonate were also detected. Compressive strength values rose with accelerated carbonation time and pore size reduction in both cement pastes.

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Section: Xrd and Sem Findingssupporting

confidence: 83%

Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties

et al. 2018

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“…Furthermore, for this formulation, the specific energy decreased considerably after 400 aging cycles. This reduction may be related to the increase in MOE of the matrix-reinforcement interface, which is the result of the densification of the material resulting from the re-precipitation of the hydration products of cement that are deposited in the lumen of cellulosic fibers, resulting in the degradation of vegetable material in a highly aggressive environment, causing it to lose its reinforcement capacity [10][11][12][13]20 . The association of cellulosic pulp with PET bottle particles did not cause variation in MOR values after the most aggressive aging conditions (400 cycles).…”

Section: Mechanical Properties Of the Compositesmentioning

confidence: 99%

“…For apparent porosity in the samples evaluated before accelerated aging and after 50 cycles, the values decreased to 21.5% and 30.9% respectively. Other authors have also reported that, after cycles of accelerated aging, there is a decrease in water absorption and apparent porosity, as well as an increase in bulk density 2,20,45 .…”

mentioning

confidence: 99%

“…To circumvent this problem, one of the evaluated alternatives is the insertion of polymeric fibers by themselves or in combination with vegetable fibers in cementitious composites [16][17][18][19][20] . The addition of synthetic fibers confers excellent physical and mechanical properties to the fibercement composites, because improvement better tensile performance and strength.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the Brazilian industry uses a mixture of fibers derived from Eucalyptus cellulosic pulp with polymeric fibers, mainly Vinyl polyacetate (PVA) and polypropylene [20][21][22] . Solid waste generated in urban centers, like packaging and food waste, is one of the most prominent environmental topics in discussions about the environment.…”

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confidence: 99%

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Cellulose Associated with Pet Bottle Waste in Cement Based Composites

et al. 2017

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The present study was to evaluate the effect of polyethylene terephthalate (PET) particle sizes on the mechanical and physical properties of extruded fiber-cement composites with different particle sizes combined to cellulose pulp in the production of fiber cement by the extrusion process. The design consisted of four formulations, one composed of 5% cellulose and the other three with 2.5% cellulosic pulp and 2.5% of PET particles with different particle sizes. Physical, mechanical and microstructural tests were performed without aging cycles and after 200 and 400 accelerated aging cycles. The degradation of vegetable fibers in the cement and the decrease of properties with aging was observed. PET particles were more resistant in alkaline environment and did not degrade. However, particle size did not exert great effect in the physical and mechanical properties of the composite. Thus, the use of PET particles shows potential as a reinforcement for fiber-cement composites.

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Effect of cementitious capillary crystalline waterproofing coating on the gas permeability of mortar

Zhang

Zuo

Yang

et al. 2019

Structural Concrete

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This study presents an experimental investigation in the effect of cementitious capillary crystalline waterproofing (CCCW) coating on the gas permeability of mortar and the mechanism how the gas permeability is affected. The gas permeability coefficient of mortar coated with or without CCCW material was measured through modified Cembureau method. The pore structure, micromorphology and hydration products of cement paste with or without CCCW coating were analyzed by the means of mercury intrusion porosimetry (MIP), scanning electron microscopyenergy disperse spectroscopy (SEM-EDS), X-ray diffraction (XRD) and thermogravimetry-differential scanning calorimetry (TG-DSC). The results showed that under the effect of CCCW coating, the gas permeability of mortar got decreased and the pore structure changed towards smaller pore sizes. SEM-EDS results exhibited that there was a large amount of ettringite filling in the pores in the paste with CCCW coating. XRD and TG-DSC analysis indicated that there was more calcium carbonate formed in the paste with CCCW coating than blank paste. The formation of ettringite in pores and increased calcium carbonate production refines the pore size distribution and densifies the cement matrix, which induces the decrease in gas permeability of mortar coated with CCCW material. K E Y W O R D SCaCO 3 , cementitious capillary crystalline waterproofing material, ettringite, gas permeability, hydration products, microstructure

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Mineralogical and microstructural changes promoted by accelerated carbonation and ageing cycles of hybrid fiber–cement composites

Cited by 64 publications

References 28 publications

Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties

Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties

Cellulose Associated with Pet Bottle Waste in Cement Based Composites

Effect of cementitious capillary crystalline waterproofing coating on the gas permeability of mortar

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