Transition zone studies of vegetable fibre-cement paste composites

Savastano, Holmer; Agopyan, Vahan

doi:10.1016/s0958-9465(98)00038-9

Cited by 136 publications

(67 citation statements)

References 12 publications

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“…Em condições de uso, o compósito já no estado endurecido entra em equilíbrio com a umidade do ambiente e a perda de água da fibra resulta em uma variação na seção transversal, como mostra a Figura 7. Como a espessura da zona de transição sisal-matriz é da ordem de 200 m [23] acredita-se que essa variação dimensional enfraqueça a zona interfacial e reduza a capacidade de transmissão de esforços. Dessa forma, espera-se que a redução da variação da seção da fibra devida à hornificação melhore a aderência fibra-matriz.…”

Section: Aderência Fibra-matrizunclassified

Influência de ciclos molhagem-secagem em fibras de sisal sobre a aderência com matrizes de cimento Portland

Ferreira¹,

Lima²,

Silva

et al. 2012

Matéria (Rio J.)

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RESUMOVisando a redução da capacidade de absorção de água de fibras ligno-celulósicas, ciclos de molhagem e secagem são usualmente utilizados na indústria de papel e celulose. Esse procedimento enrijece a estrutura polimérica das fibro-células (processo conhecido como hornificação) resultando assim em maior estabilidade dimensional da fibra. No presente estudo foi avaliada a influência da hornificação de fibras de sisal no seu comportamento físico (variações dimensionais e absorção de água), mecânico (comportamento sob cargas de tração direta) e microestrutural (modificações superficiais da fibra e da estrutura das fibro-células). Ensaios de arrancamento da fibra de sisal em matriz de cimento portland foram realizados, utilizando comprimentos de embebimento de 25 mm e 50 mm, com o objetivo de verificar se a possível estabilidade dimensional decorrente da hornificação aumentava a adesão fibra-matriz. Os resultados indicaram maior estabilidade dimensional, redução na capacidade de absorção de água, aumento na resistência à tração e capacidade de deformação e redução no módulo de elasticidade da fibra de sisal com a hornificação. Acréscimos na carga de arrancamento foram observados indicando uma maior aderência da fibra hornificada à matriz de cimento. Palavras-chave:Fibras naturais, Sisal, Interface, Resistência ao arrancamento, Hornificação ABSTRACT Aiming a reduction in the water absorption capacity of lingo-cellulosic fibers, wetting and drying cycles are usually performed in the industry of paper and cellulose. This procedure stiffens the polymeric structure of the fiber-cells (process known as hornification) resulting in a higher dimensional stability. In the present work it was investigated if the dimensional stability, obtained from the hornification process, can imporove the adhesion of the sisal fiber in a Portland cement matrix. In order to study the fiber-matrix bond adhesion pull-out tests were performed in embedment lengths of 25mm and 50mm. Furthermore, it was investigated the influence of the hornification in the physical behavior (dimensional variation and water absorption), mechanical (behavior under tensile loading) and microstructural (surface modifications of the fiber and changes in the fiber-cell structure). The results indicate a higher dimensional stability, reduction in the water absorption capacity, increase in the tensile strength and strain capacity and reduction in the modulus of elasticity with the hornification. The pull-out load increased which indicates a higher bond strength in the hornified fiber with the cementitious matrix.

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Section: Aderência Fibra-matrizunclassified

Influência de ciclos molhagem-secagem em fibras de sisal sobre a aderência com matrizes de cimento Portland

Ferreira¹,

Lima²,

Silva

et al. 2012

Matéria (Rio J.)

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“…(Table 1). It is interesting to note that countries such as Brazil which have an exceptional range of flora have a wide range of fibers to experiment with, and research in this domain is very active [13,14].…”

Section: What Does the Term "Agro-concrete" Mean?mentioning

confidence: 99%

“…The bulk density of hemp shiv is measured in a cylindrical mould with a loose packing and without compaction. The typical value obtained is about 100 kg/m 3 [8,13,65]. The particle size distribution of bio-aggregate may be studied via sieving method and/or image analysis [8,15].…”

Section: Properties Of Plant Aggregatementioning

confidence: 99%

Overview on Biobased Building Material made with plant aggregate

Amziane

Sonebi

2016

RILEM Tech Lett

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Global warming, energy savings, and life cycle analysis issues are factors that have contributed to the rapid expansion of plant-based materials for buildings, which can be qualified as environmental-friendly, sustainable and efficient multifunctional materials. This review presents an overview on the several possibilities developed worldwide about the use of plant aggregate to design bio-based building materials. The use of crushed vegetal aggregates such as hemp (shiv), flax, coconut shells and other plants associated to mineral binder represents the most popular solution adopted in the beginning of this revolution in building materials. Vegetal aggregates are generally highly porous with a low apparent density and a complex architecture marked by a multi-scale porosity. These geometrical characteristics result in a high capacity to absorb sounds and have hygro-thermal transfer ability. This is one of the essential characteristics which differ of vegetal concrete compared to the tradition mineral-based concretes. In addition, the high flexibility of the aggregates leads to a non-fragile elasto-plastic behavior and a high deformability under stress, lack of fracturing and marked ductility with absorbance of the strains ever after having reached the maximum mechanical strength. Due to the sensitivity to moisture, the assessment of the durability of vegetal concrete constitutes one of the next scientific challenging of bio-based building materials.

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“…Based on an experimental study by Ruben and Braker [7], it was found that concrete containing coconut fibre not just bring several improvement in concrete characteristics but also reduces environment pollution factors. Savastano and Agopyan [8] reported that the combination of short coconut fibres with ordinary Portland cement has presented a significant increase in toughness. Several factors such as properties, volume fraction, distribution and orientation of fibre are identified to be influenced the physical and mechanical properties of concrete.…”

Section: Concrete Containing Coconut Fibrementioning

confidence: 99%

Effect of Pelletized Coconut Fibre on the Compressive Strength of Foamed Concrete

Jaini

Mokhatar

Yusof

et al. 2016

MATEC Web of Conferences

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Abstract. Foamed concrete is a controlled low density ranging from 400kg/m 3 to 1800kg/m 3 , and hence suitable for the construction of buildings and infrastructures. The uniqueness of foamed concrete is does not use aggregates in order to retain low density. Foamed concrete contains only cement, sand, water and foam agent. Therefore, the consumption of cement is higher in producing a good quality and strength of foamed concrete. Without the present of aggregates, the compressive strength of foamed concrete can only achieve as high as 15MPa. Therefore, this study aims to introduce the pelletized coconut fibre aggregate to reduce the consumption of cement but able to enhance the compressive strength. In the experimental study, forty-five (45) cube samples of foamed concrete with density 1600kg/m 3 were prepared with different volume fractions of pelletized coconut fibre aggregate. All cube samples were tested using the compression test to obtain compressive strength. The results showed that the compressive strength of foamed concrete containing 5%, 10%, 15% and 20% of pelletized coconut fibre aggregate are 9.6MPa, 11.4MPa, 14.6MPa and 13.4MPa respectively. It is in fact higher than the controlled foamed concrete that only achieves 9MPa. It is found that the pelletized coconut fibre aggregate indicates a good potential to enhance the compressive strength of foamed concrete.

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Transition zone studies of vegetable fibre-cement paste composites

Cited by 136 publications

References 12 publications

Influência de ciclos molhagem-secagem em fibras de sisal sobre a aderência com matrizes de cimento Portland

Influência de ciclos molhagem-secagem em fibras de sisal sobre a aderência com matrizes de cimento Portland

Overview on Biobased Building Material made with plant aggregate

Effect of Pelletized Coconut Fibre on the Compressive Strength of Foamed Concrete

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