Durabilidade de argamassas modificadas por polimeros e reforçadas com fibras vegetais / Durability of fiber-cement polimer modify

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Several researches on vegetal-fiber-cement composites have been developed aiming to solve problems related to the banishment of asbestos and environmental damages due to deposition or burnirng of agro-industry residues. The durability of the cellulose-cement composites is a key factor to introduce such material in the market. Several researches have been developed aiming to avoid the degradation of vegetable fiber-cement, some of them using chemically treated fibers and others modifying the matrix. Polymers have been used in concrete and mortar production to increase the durability. Composite degradation can be controled by polymers that modify the fiber-matrix bond and the amount of water absorption. The goal of this work was to characterize the physical and the mechanical properties of cellulose-cement composites modified by a polymer and to evaluate the subsequent durability of these materials. The dispersion of an acrylic based polymer was evaluated with two types of composites: one with cellulose pulps (Eucalyptus and wastepaper) and another with Pinus caribaea particles. The physical properties under observation were water absorption by immersion, apparent void volume and bulk density. The mechanical properties of toughness and modulus of rupture were determined by flexural test. The dynamic elasticity modulus was obtained by ultrasonic method. Samples were subjected to natural aging tests and to accelerated-aging tests by repeated soak and dry cycles and warm-water immersion. By the range of composites analyzed, the use of the polymer improves the initial mechanical properties of composites and promotes a significant decrease of the water absorption. The scanning electron microscopy (SEM) allowed to verify the modification of the morphologic characteristic of the composite with the polymeric addition and the preservation of the fibers along the time. The use of the polymer improved the mechanical performance of the composite in the first ages, besides promoting a significant reduction of the capacity of absorption of water, denoting its adaptation to increase the durability of the composite

ASSUNTO(S)

durabilidade (engenharia) compostos fibrosos polimers fiber composite scanning eletron microscope concrete microscopia eletronica de varredura polimeros concreto - mistura residuos vegetais durability moisture vegetal residue

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