Carbonation Model and Prediction of Polyvinyl Alcohol Fiber Concrete with Fiber Length and Content Effects

Zuyun Luo,Heli Ji,Chuanchuan Zhang,Xinhua Yang

doi:10.1186/s40069-022-00503-1

Abstract

Durability is an important aspect of reliability of concrete structures. In order to establish the carbonation model of polyvinyl alcohol (PVA) fiber concrete including the influences of PVA fiber length and volume content, a series of accelerated carbonation experiments were carried out on the normal concrete specimens and PVA fiber concrete specimens with fiber lengths of 3 mm, 6 mm, 12 mm and 18 mm and fiber volume contents of 0.1%, 0.3%, 0.5%, 0.75%, 1.0% and 1.5%, respectively. The experimental conditions remained at temperature of 20 ℃, humidity of 70%, and carbon dioxide concentration of 20%. It was found that the addition of PVA fibers could improve the carbonation resistance of concrete considerably. Within the investigated range of fiber length and content, the carbonation resistance of concrete is first strengthened and then weakened with increasing PVA fiber length or content. The quadratic carbonation depth prediction model could characterize the influences of PVA fiber length and content better than the linear model. The carbon dioxide diffusion equation was established by introducing a PVA fiber influence factor and its parameters were determined from the carbonation depth prediction model. The carbonation process of PVA fiber concrete under the accelerated carbonation experiment condition was simulated. Both the model and the numerical method were validated by comparison between the experimental and numerical results. Finally, the influences of added PVA fibers on the carbonation life and durability of reinforced concrete components were further studied numerically. The results showed that compared with the normal concrete component, the durability of PVA fiber concrete components is significantly improved.

Highlights

As one of the most widely used construction and building materials, concrete has high compressive strength, but low tensile and bending strength, poor ductility, and low fracture toughness (An et al, 2014; Pacheco-Torgal et al, 2012; Samarakkody et al, 2017)
Some rapid carbonation experiments were performed on the normal concrete and polyvinyl alcohol (PVA) fiber concrete specimens, and the influences of PVA fiber length and content on the concrete carbonation are studied to establish the carbonation model of PVA fiber concrete including the influences of PVA fiber length and volume content
6 Conclusions In this paper, the influences of fiber length and volume content on the carbonation behavior of PVA fiber concrete are investigated by the accelerated carbonation experiments and numerical simulations

Summary

Introduction

As one of the most widely used construction and building materials, concrete has high compressive strength, but low tensile and bending strength, poor ductility, and low fracture toughness (An et al, 2014; Pacheco-Torgal et al, 2012; Samarakkody et al, 2017). Carbon dioxide in the environment intrudes into porous concrete and dissolves in the pore solution to form carbonic acid, which reacts with the calcium hydroxide around the pores to form calcium carbonate (Mi et al, 2019; Omikrine Metalssi et al, 2020). This reaction continues until the pH value in the pore solution drops to the range of 8.5 ~ 9.0. In 2020, Liu et al (2020) studied the carbonation rate of concrete in different environments, and proposed a carbonation depth prediction model considering the effects of temperature, relative humidity and carbon dioxide concentration. As a simple application, the model was used to numerically evaluate the durability of reinforced PVA fiber concrete components after validation

Experimental Method

Experimental Procedures

Effects of PVA Fiber Length and Content on Carbonation

Conclusions