Studies On The Performance Of Vegetable Fiber Reinforced Cement-based Composites

As a kind of low cost and renewable resource, vegetable fibers have been chosen as the reinforced material of cement-based composites, and research on the material and its application have important practical engineering meanings. Since 1980s, more and more tests and applications have been finished by a growing number of countries, especially the developing countries where possess abound of vegetable fibers, but it still has something remains to be further studied. The physical and mechanical properties of low cost vegetable fibers reinforced cement-based composites, the erosion mechanism and improvements on the durability of these composites are considered as emphasis in tests and studies in this paper.The physical and mechanical properties of three dosages (that is 1.4kg/m~3, 2.8kg/m~3 and 5.6kg/m~3 respectively) of vegetable fibers in concrete have been tested. The results show that vegetable fibers can be dispersed uniformly in the composites, and that the performances of the concrete have been improved efficiently. Though the compressive strengths of the fiber reinforced concrete become lower a little than ordinary one, the split tensile, bending, tensile strengths, and the toughness have been improved efficiently compared with ordinary concrete. From the point of view to improve the toughness of the concrete, the optimal dosage of vegetable fiber is 2.8kg/m~3.Admixing vegetable fibers into concrete can reduce the plastic constraint crack at early age and improve its crack resistance performance greatly. The anti-cracking experiments of cement mortar show that the cracks can be reduced and be slim or even be eliminated when a small fraction of fibers are be added.By micro-analysis on the aging fibers, it indicates that attack of alkali hydrates to vegetable fibers is serious and the flexibility becomes lower and the brittleness becomes increase for the calcium hydroxide crystal conglomerated in the fiber's bosom. The tensile strength of the fiber cement-based composites is lower under the long-term effect of dry and wet cycles.Through immersing the fibers in polymer solution prior to being incorporated in...