Fabric-reinforced cementitious matrix (FRCM) with synthetic reinforcements has been employed in a... more Fabric-reinforced cementitious matrix (FRCM) with synthetic reinforcements has been employed in a wide of precast products in the current market. However, FRCM employing cellulosic fibers has been limited in civil engineering applications due to the absence of a well-established standardization. Cellulosic textile structures present many advantages to strengthen cementitious composites, which depend on the type of natural fiber, forms that are organized (e.g., bundle fibers or twisted yarns), and ligaments. This study aimed to develop an overview of FRCM to identify how cellulosic textile has been designed and processed in research, according to type, shape, properties, durability, and matrix formulations. The main findings were as follows: (i) bundle fibers and low entangled yarns presented potential to increase the tensile properties; (ii) woven canvas prevailed in the cementitious composite applications; (iii) 3 and 4 layers of fabrics presented better mechanical performance than few layer samples; (iv) the alkaline treatment is one of most employment to improve the adherence; (v) to prevent cellulose degradation, resin coatings (epoxy) or pozzolan additions (silica, metakaolin, nanoclay, ashes from agricultural wastes) are employed. Future investigations are necessary to improve cellulosic FRCM; opportunities for study in textile area are proposed: enlargement of fabric technologies, hybrid fibers, machinery technology (3D fabrics, complex knit) adaptation to use cellulosic fibers, and new architectural design for cellulosic FRCM applications (curved forms and sizes).
The increased emphasis placed on lamb production in Brazil points to the need for a better knowle... more The increased emphasis placed on lamb production in Brazil points to the need for a better knowledge of the annual pattern of reproductive activity in ewe lambs. This study evaluates the annual estrous activity pattern of hair and wool ewe lambs raised in southeast Brazil. Estrous characteristics were recorded for 12 months in ten Santa Inês and 21 Romney Marsh and Suffolk ewe lambs. Santa Inês ewe lambs exhibited a greater length of the normal estrous cycle (14 to 19 days) than Romney Marsh and Suffolk ewe lambs (17.0 ± 0.1 days vs. 16.5 ± 0.2 and 15.9 ± 0.2 days). All the ewe lambs presented a greater number of periods of estrus per animal per month for single estrous cycles (up to 26 days) during autumn and winter. During spring and summer there was a reduction of this number but this decline varied according to the breed. For Santa Inês ewe lambs the reduction was only significant in the summer. For wool ewe lambs the reduction was significant in both seasons but was more accentuated for Romney Marsh. The Romney Marsh ewe lambs had a more restricted breeding season than Suffolk and both presented optimal estrus activity in autumn and winter. Santa Inês ewe lambs had a continuous distribution of estrous cycles along the year, although presenting a reduction in the number of estrous periods in the summer. The ewe lambs of three breeds presented characteristics of sexual immaturity, like irregular estrous cycles and silent ovulations.
Fabric-reinforced cementitious matrix (FRCM) with synthetic reinforcements has been employed in a... more Fabric-reinforced cementitious matrix (FRCM) with synthetic reinforcements has been employed in a wide of precast products in the current market. However, FRCM employing cellulosic fibers has been limited in civil engineering applications due to the absence of a well-established standardization. Cellulosic textile structures present many advantages to strengthen cementitious composites, which depend on the type of natural fiber, forms that are organized (e.g., bundle fibers or twisted yarns), and ligaments. This study aimed to develop an overview of FRCM to identify how cellulosic textile has been designed and processed in research, according to type, shape, properties, durability, and matrix formulations. The main findings were as follows: (i) bundle fibers and low entangled yarns presented potential to increase the tensile properties; (ii) woven canvas prevailed in the cementitious composite applications; (iii) 3 and 4 layers of fabrics presented better mechanical performance than few layer samples; (iv) the alkaline treatment is one of most employment to improve the adherence; (v) to prevent cellulose degradation, resin coatings (epoxy) or pozzolan additions (silica, metakaolin, nanoclay, ashes from agricultural wastes) are employed. Future investigations are necessary to improve cellulosic FRCM; opportunities for study in textile area are proposed: enlargement of fabric technologies, hybrid fibers, machinery technology (3D fabrics, complex knit) adaptation to use cellulosic fibers, and new architectural design for cellulosic FRCM applications (curved forms and sizes).
The increased emphasis placed on lamb production in Brazil points to the need for a better knowle... more The increased emphasis placed on lamb production in Brazil points to the need for a better knowledge of the annual pattern of reproductive activity in ewe lambs. This study evaluates the annual estrous activity pattern of hair and wool ewe lambs raised in southeast Brazil. Estrous characteristics were recorded for 12 months in ten Santa Inês and 21 Romney Marsh and Suffolk ewe lambs. Santa Inês ewe lambs exhibited a greater length of the normal estrous cycle (14 to 19 days) than Romney Marsh and Suffolk ewe lambs (17.0 ± 0.1 days vs. 16.5 ± 0.2 and 15.9 ± 0.2 days). All the ewe lambs presented a greater number of periods of estrus per animal per month for single estrous cycles (up to 26 days) during autumn and winter. During spring and summer there was a reduction of this number but this decline varied according to the breed. For Santa Inês ewe lambs the reduction was only significant in the summer. For wool ewe lambs the reduction was significant in both seasons but was more accentuated for Romney Marsh. The Romney Marsh ewe lambs had a more restricted breeding season than Suffolk and both presented optimal estrus activity in autumn and winter. Santa Inês ewe lambs had a continuous distribution of estrous cycles along the year, although presenting a reduction in the number of estrous periods in the summer. The ewe lambs of three breeds presented characteristics of sexual immaturity, like irregular estrous cycles and silent ovulations.
Uploads
Papers by Lia Coelho