Effect of PVA fiber on durability of cementitious composite containing nano-SiO2

Abstract

In the current investigation, the influence of polyvinyl alcohol (PVA) fibers on flowability and durability of cementitious composite containing fly ash and nano-SiO2 was evaluated. PVA fibers were added into the composite at a volume fraction of 0.3%, 0.6%, 0.9%, and 1.2%. The flowability of the fresh cementitious composite was assessed using slump flow. The durability of cementitious composite includes carbonation resistance, permeability resistance, cracking resistance as well as freezing-thawing resistance, which were evaluated by the depth of carbonation, the water permeability height, cracking resistance ratio of the specimens, and relative dynamic elastic modulus of samples after freeze-thaw cycles, respectively. The results indicated that addition of PVA fibers had a little disadvantageous influence on flowability of cementitious composite, and the flowability of the fresh mixtures decreased with increases in PVA fiber content. Incorporation of PVA fibers significantly improved the durability of cementitious composites regardless of addition of nano-particles. When the fiber content was less than 1.2%, the durability indices of permeability resistance and cracking resistance increased with fiber content. However, the durability indices of carbonation resistance and freezing-thawing resistance began to decrease as the fiber dosage increased from 0.9% to 1.2%. The fiber reinforced cementitious composite exhibited better durability due to addition of nano-SiO2 particles. Nano-SiO2 particle improves microscopic structure of fiber reinforced cementitious composites, and the nano-particles are beneficial for PVA fibers to play the role of reinforcement in cementitious composites.

Pore Structural and Fractal Analysis of the Influence of Fly Ash and Silica Fume on the Mechanical Property and Abrasion Resistance of Concrete

“…As shown in Table 1, the specific surface of silica fume is about 43 times larger than that of fly ash in this study. Thus, the super fine silica fume particles could react with Ca(OH)2 very rapidly to produce a large amount of additional C-S-H at early age, densifying the microstructure of concrete and enhancing the mechanical strengths, which is in accordance with previous studies 6,47,48 .…”

Compressive Strength Prediction of PVA Fiber-Reinforced Cementitious Composites Containing Nano-SiO2 Using BP Neural Network

“…During the trial, three experimental levels were designed for each parameter, whose values corresponding to the changes in each level are presented in Table 8 below, which were selected based on experience. Among them, the number of neurons was ascertained by the following empirical formula: l = √ n + m + a, a ∈ [1,10], where a is an integer obtained from the boundary of 1-10. The training times were determined according to the convergence times of the trial test.…”

“…Concrete is a widely used building material in engineering constructions [1]. With the large-scale construction of long-span bridges, super-high-rise buildings, high-grade highways, large-scale water conservancy facilities, and cross harbor tunnels, concrete materials are endowed with higher expectations [2].…”

“…With the large-scale construction of long-span bridges, super-high-rise buildings, high-grade highways, large-scale water conservancy facilities, and cross harbor tunnels, concrete materials are endowed with higher expectations [2]. More problems have been caused by traditional concrete materials, such as the crack propagation inside concrete materials and the lack of durability [1]. Therefore, it is crucial to optimize the mix proportion and improve the compressive strength of concrete [3].…”

Experimental study on photocatalytic degradation efficiency of mixed crystal nano-TiO2 concrete

“…Test results showed that the diatom-FeOx composite exhibited high activity in catalyzing the photodegradation of Rh-6G. Zhang et al [11] evaluated and discussed the effects of nano-SiO 2 on the photocatalytic behavior and durability of cementitious composite incorporated with nano-SiO 2 . The results indicated that the nano-SiO 2 could dramatically improve the photocatalytic performance and durability of cementitious composites.…”