Mechanics of natural curauá textile-reinforced concrete

Abstract

In the present work, textile-reinforced concrete (TRC) specimens were produced using high-performance natural curauá unidirectional fabrics as reinforcement. Portland cement was partially replaced by pozzolanic materials to produce a matrix with low calcium hydroxide content. Composites with different numbers of layers and thicknesses were produced. Their mechanical behaviour was evaluated through tensile testing. Crack formation was investigated using an image capture procedure and a digital image correlation (DIC) methodology. From the DIC analysis, it was possible to provide an estimate of the number of cracks, the mean crack spacing and width during the tensile tests. The curauá textile was shown to be a promising reinforcement, resulting in a composite with multiple cracking formation and strain-hardening behaviour. This newly developed composite showed similar mechanical behaviour to that of man-made fibre-reinforced composites. Combined with its low cost and sustainability characteristics, the curauá TRC may represent a good alternative to conventional construction materials.

On the mechanical properties and crack pattern analysis of a strain-hardening cement-based composite reinforced by natural sisal fibers

“…The measurements were observed at the end of stage III when the composites reached its maximum strength. The cracking patterns are compatible with those mentioned by other authors [19,25,31,32], with a wide variance which may be explained by the fiber's morphology and their distribution in the matrix. Compared to SPEC 5 and SPEC 6, SPEC 7 presented the largest crack width and the smallest number of cracks, demonstrating that these parameters are inversely proportional, which is explained by the higher stress concentration in each crack due to its smaller number.…”

“…Furthermore, SILVA JUNIOR et al [25] used a volumetric fraction equal to 6% in composites reinforced by curauá fibers and reached 10.2 MPa, 15% lower than the achievement in the present work. However, it is worth mentioning that the composite by SOUZA et al [19], with 8.5% volume (curauá fibers), presented the highest strength among all. In general, the authors describe a similar strain capacity at failure, except for TEIXEIRA and SILVA [32] and their three layers curauá composite, which exhibited a strain result 68.8% higher than specimens presented in this work.…”

“…For comparison, the composite mechanical behavior in the present work was confronted by the results of other authors [19,25,31,32] who also used natural fibers in cement matrices. All these authors used the same specimen geometry adopted in the present work, except for thickness which varies according to the parameters such as the number of fiber layers, fibers volume, and manufacturing technique.…”

“…The use of natural fibers in cementitious matrix composites can considerably improve the physicalmechanical properties of the material [4,5,[7][8][9], can significantly reduce the material cost [10,11], and can reduce the environmental impact caused by the production process of the mixing materials [12]. Consequently, several configurations of natural fibers have been mechanically explored in cement-based composites, such as the textile form [13][14][15], short and randomly dispersed in the matrix [16][17][18], or in a continuous and aligned way [19][20][21]. Despite the benefits cited, natural fibers have a high ability to absorb moisture [22] and may develop durability problems when in the alkaline environment of the cement matrix [1,23].…”

“…On the other hand, continuous fiber-reinforced cement composites can be considered high-performance construction materials due to their superior tensile strength and ductility [19,25,31,32]. The improved mechanical properties and its considerable strength make this kind of material suitable for use as structural panels, impact and blast resistance, repair, and retrofit applications [33].…”