Experimental Research On Cellulose-PVA Hybrid Fiber Reinforced Concrete Performance

Concrete is the largest amount of civil engineering structural material. However, the concrete itself has the shortcomings of low tensile strength, easy cracking and so on. The fiber is often used to improve and enhance the performance of concrete. Studies have shown that single fibers tend to certain limitations and hybrid fiber is capable of producing more excellent performance concrete material. At present, there are few reports about the study on the mechanical properties, durability and the correlation between the indexes of the hybrid fiber reinforced concrete.This paper intends to mix two types of non-metallic fiber which are polyvinyl alcohol and cellulose, to carry out PVA-cellulose hybrid fiber reinforced concrete work, mechanical properties and durability testing and research on the age and the intensity level of the mixed mechanical properties and durability of fiber concrete which give relevance hybrid mechanical properties of fiber concrete and durability indexes by regression analysis. The main contents are as follows:(1)To C40 concrete for the concrete matrix, test carried out the slump test of PVA-cellulose hybrid fiber, single doped PVA fibers or cellulose fibers and plain concrete. The results show that PVA cellulose hybrid fiber can reduce the concrete slump, in which PVA fiber play main role.(2)To C40 concrete for the concrete matrix, test carried out the PVA-cellulose hybrid fiber, single doped PVA fibers or cellulose fibers, plain concrete in different age of compressive strength, splitting tensile strength, resistivity, chloride ion penetration test. Research results show that hybrid fiber concrete is better than the single doped PVA fibers or cellulose fibers that the compressive strength, splitting tensile strength, resistivity, resistance to chloride ion permeability of fibre concrete have obvious advantages,The later stage of the hydration reaction of hybrid fiber concrete reinforced concrete in tension and compression is relatively high and the toughness is good.(3)To C40 concrete for the concrete matrix, test maintained a constant fiber content but change another to research on the impact on performance of hybrid fiber reinforced concrete as the single fiber content changed. The results show that: PVA fiber 1.2kg/m3 and 0.9kg/m3(cellulose) are the optimal dosage; PVA fibers of different period or cellulose fiber has different mixed effect.(4)To C30、C40、C50 concrete for the concrete matrix, test carried out the mechanical performance and durability testing of mixed 1.2kg/m3 of PVA fiber and 0.9kg/m3 cellulose fiber concrete. The results show that: the compressive strength of concrete double-doped fiber, splitting tensile strength, resistance increases with age and the intensity level increases;chloride ion permeability coefficient with age and intensity level decreases; the various indicators in different fiber mixed in the same age or different ages in the same fiber mixed have the different rate of changes.(5)There are the correlation analysis of the performance index of hybrid fiber concrete. The results showed that: a linear or non-linear regression relationship is between the hybrid fiber reinforced concrete performance indicators of the same age or between different ages.