Mechanical Properties and Carbonation Durability of Engineered Cementitious Composites Reinforced by Polypropylene and Hydrophilic Polyvinyl Alcohol Fibers.

Wei Zhang,Fuquan Ma,Chenglong Yin,Zhiyi Huang

doi:10.3390/ma11071147

Wei Zhang, Fuquan Ma + Show 2 more

Open Access

https://doi.org/10.3390/ma11071147

Copy DOI

Journal: Materials	Publication Date: Jul 5, 2018
Citations: 34	License type: CC BY 4.0

Affiliation: Zhejiang University

Abstract

Herein, the mechanical properties and carbonation durability of engineered cementitious composites (ECC) were studied. For the cost-efficient utilization of ECC materials, different types of specimens were cast with polypropylene (PP) and hydrophilic polyvinyl alcohol (HPVA) fibers. The compressive strength, Poisson’s ratio, strength-deflection curves, cracking/post-cracking strength, impact index, and tensile strain-stress curves of two types of ECC materials, with differing fiber contents of 0 vol %, 1 vol %, 1.5 vol %, and 2 vol %, were investigated with the use of compressive tests, four-point bending tests, drop-weight tests, and uniaxial tensile tests. In addition, the matrix microstructure and failure morphology of the fiber in the ECC materials were studied by scanning electron microscopy (SEM) analysis. Furthermore, carbonation tests and characterization of steel corrosion after carbonization were employed to study durability resistance. The results indicated that for both PP fiber- and HPVA fiber-reinforced ECCs, the compressive strength first increases and then decreases as fiber content increases from 0 vol % to 2 vol %, reaching a maximum at 1 vol % fiber content. The bending strength, deformation capacity, and impact resistance show significant improvement with increasing fiber content. The ECC material reinforced with 2 vol % PP fiber shows superior carbonized durability with a maximum carbonation depth of only 0.8 mm.

Highlights

The inherent quasi-brittle behavior of conventional cementitious materials produces a lower strain capacity and damage tolerance, leading to poor safety and low durability of infrastructures such as buildings, bridges, tunnels, etc. [1,2]
This study investigated the mechanical properties and carbonation durability of Engineered cementitious composites (ECC) with various volume fractions of PP fibers and hydrophilic polyvinyl alcohol (HPVA) fibers
Cost-efficient ECC materials can be obtained by addition of PP fibers, HPVA fibers, and relatively coarse sand

Summary

Introduction

The inherent quasi-brittle behavior of conventional cementitious materials produces a lower strain capacity and damage tolerance, leading to poor safety and low durability of infrastructures such as buildings, bridges, tunnels, etc. [1,2]. A strain hardening cementitious composite (SHCC) containing high volumes of polymer fibers (up to 2 vol %) has been investigated and utilized for many applications, as it has been found to exhibit a pseudo strain-hardening ability under direct tensile stress [3,4,5]. In comparison to ordinary concrete, the main advantages of SHCC materials include significantly higher ductility and deformation capacity after initial cracking; SHCC materials possess a higher load-carrying ability, enhancing safety and durability for structures under catastrophic conditions [6,7]. Engineered cementitious composites (ECC) are the most typical type of SHCCs, and were first reported by Li et al, in 1994 [8,9]. Its tensile strain capacity can reach 3–5%, Materials 2018, 11, 1147; doi:10.3390/ma11071147 www.mdpi.com/journal/materials

Objectives

Methods

Discussion

Conclusion