Durability of alkali-sensitive sisal and coconut fibres in cement mortar composites

Filho, Romildo Dias Tolêdo; Scrivener, Karen; England, G. L.; Ghavami, Khosrow

doi:10.1016/s0958-9465(99)00039-6

Cited by 407 publications

(137 citation statements)

References 4 publications

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“…It is well known that this lack of durability is mainly caused, on the one hand, by the calcium hydroxide (portlandite) of the matrix, which degrades the fibers, and, on the other, by changes in environmental moisture, which induce dimensional changes in the vegetable fibers and hence loss of physical contact with the matrix [25][26][27]. To overcome the problem of the calcium hydroxide component, several strategies have been used, such as pozzolanic additions to precipitate the portlandite as calcium silicate hydrate [28][29][30][31][32][33][34][35] or carbonation treatments with CO2 to precipitate the portlandite as calcium carbonate [36].…”

Section: Introductionmentioning

confidence: 99%

Natural fiber nonwoven reinforced cement composites as sustainable materials for building envelopes

Claramunt

Fernández-Carrasco

Ventura

et al. 2016

Construction and Building Materials

109

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This experimental research analyzes the mechanical performance and durability of façade pieces based on Portland cement matrix and flax nonwovens as reinforcement. Two types of pozzolanic additions (silica fume and metakaolin) combined with nonwovens subjected to different treatments to decrease their water absorption are analyzed as potential materials for fiber-cement sheets for building envelopes with high strength and durability. For this purpose, on the one hand, the mechanical performance and chemical composition of various ternary compositions were studied. On the other hand, various treatments were performed on the nonwovens and the nonwoven-matrix adherence was also analyzed. Finally, composites were prepared from some selected treated nonwovens and matrix mixtures, and their mechanical properties and durability were evaluated under four-point bending tests after 28 days of curing in a humidity chamber and after accelerated aging. The composites developed with the treated nonwovens presented very high performance combined with enough durability to be potential candidates for the development of sustainable materials for building envelopes. Highlights-Mechanical performance and durability of OPC/flax nonwovens composites for façade pieces is explored -The effect of two pozzolanic additions combined with nonwoven treatment is evaluated -Significant improvements in the durability using treated nonwovens 3

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Section: Introductionmentioning

confidence: 99%

Natural fiber nonwoven reinforced cement composites as sustainable materials for building envelopes

Claramunt

Fernández-Carrasco

Ventura

et al. 2016

Construction and Building Materials

109

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“…However, vegetable fibre cement composites undergo an ageing process in humid environments in which they may suffer a reduction in strength and toughness. This durability problem is associated with an increase in fibre fracture and decrease in fibre pull-out due to a combination of weakening of the fibres by alkali attack, fibre mineralisation due to migration of hydration products to lumens and spaces and volume variation in these fibres due to their high water absorption [1][2][3][4]. To enhance the durability performance of vegetable fibre reinforced cement-based composites several approaches have been studied including fibre impregnation with blocking agents and water-repellent agents, either singly or in tandem, sealing of the matrix pore system, reduction of matrix alkalinity and combinations of fibre impregnation and matrix modification [2,3].…”

Section: Introductionmentioning

confidence: 99%

Development of vegetable fibre–mortar composites of improved durability

Filho

Ghavami

England

et al. 2003

Cement and Concrete Composites

Self Cite

381

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The primary concern for vegetable fibre reinforced mortar composites (VFRMC) is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength and toughness as a result of weakening of the fibres by a combination of alkali attack and mineralisation through the migration of hydration products to lumens and spaces. This paper presents several approaches used to improve the durability performance of VFRMCs incorporating sisal and coconut fibres. These include carbonation of the matrix in a CO 2 -rich environment; the immersion of fibres in slurried silica fume prior to incorporation in the ordinary Portland cement (OPC) matrix; partial replacement of OPC matrix by undensified silica fume or blast-furnace slag and a combination of fibre immersion in slurried silica fume and cement replacement. The durability of the modified VFRMC was studied by determining the effects of ageing in water, exposure to cycles of wetting and drying and open air weathering on the microstructures and flexural behaviour of the composites. Immersion of natural fibres in a silica fume slurry before their addition to cement-based composites was found to be an effective means of reducing embrittlement of the composite in the environments studied. Early cure of composites in a CO2-rich environment and the partial replacement of OPC by undensified silica fume were also efficient approaches in obtaining a composite of improved durability. The use of slag as a partial cement replacement had no effect on reducing the embrittlement of the composite.

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“…Based on the analysis of RCF and hardened cement paste spectrograms one can suggest that partial mixing of hydration products of cement clinker minerals occurred around the fiber surface layer [12,13]. It shall be noted that higher content of calcium ions (Table 1) might be related to formation of crystallization centers in the contact zone between RCF and cement matrix, which is followed by setting of Ca(ОН) 2 crystals [14,15]. Microstructure of fiber reinforced foam concrete was studied for advance investigation of structure formation processes in deep layers of fiber reinforced foam concrete.…”

Section: Resultsmentioning

confidence: 99%

“…First of all, new formations have high density which is proved by close packing of hydration products [12,15]. Besides, a thin network of microfibrillar fibers was found all over the RCF surface, their diameter being between 50 and 300 nm (Fig.…”

Section: Resultsmentioning

confidence: 99%

Influence of cellulose fibers on structure and properties of fiber reinforced foam concrete

Федоров

Mestnikov

2018

MATEC Web Conf.

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Abstract. One of the promising means of foamed concrete quality improvement is micro-reinforcement by adding synthetic and mineral fibers to the base mix. This research is the first to investigate peculiarities of using recycled cellulose fiber extracted from waste paper for obtaining fiber reinforced foam concrete. The paper presents results of experimental research on the influence of cellulose fibers on structure and properties of fiber reinforced foam concrete by using methods of chemical analysis and scanning electron microscopy. The research determines peculiarities of new formations appearance and densification of binder hydration products in the contact zone between fiber and cement matrix, which boost mechanical strength of fiber reinforced foam concrete. Physico-mechanical properties of fiber reinforced foam concrete were defined depending on the amount of recycled cellulose fiber added to the base mix. It was found that the use of recycled cellulose fibers allows obtaining structural thermal insulating fiber reinforced foam concretes of non-autoclaved hardening of brand D600 with regard to mean density with the following improved properties: compressive strength increased by 35% compared to basic samples, higher stability of foamed concrete mix and decreased shrinkage deformation.

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Durability of alkali-sensitive sisal and coconut fibres in cement mortar composites

Cited by 407 publications

References 4 publications

Natural fiber nonwoven reinforced cement composites as sustainable materials for building envelopes

Natural fiber nonwoven reinforced cement composites as sustainable materials for building envelopes

Development of vegetable fibre–mortar composites of improved durability

Influence of cellulose fibers on structure and properties of fiber reinforced foam concrete

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