Preparation And Performance Of Original Bamboo Fibers Reinforced Concrete Composites

The fiber reinforcement for cement could overcome some shortcomings of concrete-based composites to a certain extent,such as improving the ratio of tension to compression,toughness and durability.Due to the consideration of energy saving and environmental protection,green and renewable bamboo fibers have been gradually drawn much attention for the use as the reinforcement for cement based composites.The present study aims to preparing bamboo fibers reinforced cement composites and providing solutions for the problem of the poor interfacial adhesion between fibers and cement which significantly reduces the reinforcing effect of bamboo fibers on cement.Therefore,the bamboo fibers were modified by using three methods with moderately low cost and easy handling.The micro-structure of the composites was characterized by nuclear magnetic resonance and scanning electron microscopy analyses.The performance of the modified bamboo fibers reinforced cement composites was evaluated in terms of flexural and compressive tests,capillary water absorption,chloride ion erosion test,dry shrinkage test,freeze-thaw cycle test and carbonization test.The interfacial bonding,porosity,flexural strength,tensile strength,toughness,impermeability,freeze-thaw resistance,and aging resistance of the composites were investigated.The results are as follows:(1)Among the composites reinforced with three kinds of modified bamboo fibers,the composites reinforced with glycerol-modified bamboo fibers have the lowest porosity and the glycerol modification for fibers significantly improves the compactness of the composites;the composites reinforced with aluminate ester modified bamboo fibers have the most uniform moisture distribution and the internal porosity size distribution in the composites is more uniform than that of the untreated fibers composites.(2)The modified bamboo fiber reinforced concrete composites have better strain hardening and multiple-cracking characteristics,and significantly improved the flexural strength,toughness,tensile strength when compared to the untreated-fibers composites.The aluminate ester modified group had 23%and 61.4%increase in the ratio of flexural strength and bending-compressive strength compared with the standard group(3)The glycerol-modified bamboo fibers reinforced cement composites have better mechanical properties and aging resistance than others.The composites exhibit certain plastic characteristics since the damaged specimens retain certain integrity.(4)The results of water absorption and chloride ion erosion tests for composites show that the addition of modified bamboo fibers influences the impermeability greatly,and the aluminate ester modified bamboo fibers composites have the best impermeability among the three kind composites.(5)The results of drying shrinkage,freeze-thaw damage and carbonization experiments showed that the glycerol modified composites have a good anti-shrink capacity.The aluminate ester modified composites have a good frost-resistance.Adding aluminate ester modified bamboo fibers can effectively slow down the aging process and expand service life of the composites.