Tensile and Anti-Spalling Properties of Direct Sprayed ECC

Abstract

The use of Engineered Cementitious Composite (ECC), which has metal-like deformation and crack opening restriction ability, as a retrofit material for structures, has been the subject of high expectations. For this application, the direct spray method has been commonly accepted. This study focused on experimentally clarifying the fundamental properties of direct sprayed ECC containing high-performance polyvinyl alcohol fibers. The experiments that were performed demonstrated that direct sprayed ECC was successfully processed and showed pseudo-strain hardening performance comparable to that of traditionally cast ECC reported in the literature. Furthermore, test results simulating concrete cover cracking due to re-bar corrosion demonstrated that direct sprayed ECC has significant potential to prolong service life of R/C members in a heavy chloride environment.

Simplified Inverse Method for Determining the Tensile Strain Capacity of Strain Hardening Cementitious Composites

“…As aforementioned, tensile ductility is the most important material property of SHCC, yet relatively large variation of tensile ductility was observed in the literature (Kanda et al 2002(Kanda et al , 2006Wang and Li 2004). To address such concern, Wang and Li (2004) have proposed using artificial flaws with prescribed size distribution as defect site initiator to create more saturated multiple cracks, resulting in more consistent tensile strain capacity among different specimens from the same batch.…”

Full Scale Processing Investigation for ECC Pre-cast Structural Element

“…ECC production has been poorly documented except for a few reports on a full-scale mixing test 4) . This study aims to obtain knowledge on quality assurance in full-scale production by a trial production in pre-cast concrete plants on a large scale.…”

“…The mix proportions used in this study are shown in Table 3., where Mix-N is based on the literature 4) and the Mix-M is nearly the same as Mix-N except for the substitution of OPC with MPC. These two mixes showed self-compacting fresh properties in laboratory mixing 3) , and slump flow values of over 500mm.…”

“…x n1 can be obtained from the relation between measured load and curvature and is a solution to the following equations (3) and (4). M max in equation (3) is the maximum moment by experiments, and B is the width of a specimen.…”

“…This paper describes the full-scale production of selfcompacting ECC with PVA fiber 3), 4) , and shows that quality assurance of fresh and mechanical properties of ECC in the plant is highly reliable, and that its tensile properties can be verified by a simple test. A statistical evaluation of tensile properties and knowledge of performance standards indispensable to the design of ECC structural members are presented.…”