Chloride induced corrosion of integral and non-integral surface treated lightweight foamed concrete
Date
2018-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: Advancement in new technologies and methods of producing foaming agents have resulted in enhanced possibility of a structurally performing lightweight concrete. Lightweight foamed concrete (LWFC) is a cement based composite material that has shown remarkable potential as a replacement to Normal Weight Concrete (NWC) for structural applications. LWFC stands as a low self-weight building material relatively compared to its counterpart, NWC. Other than reduced self-weight, it also possesses desirable properties such as good thermal insulation, excellent fire resistance, and high workability and self-levelling. Technical and engineering unfamiliarity of LWFC has contributed to inhibiting the material’s wider use and advancement for structural application. In addition to the above, limited literature on the material’s durability properties and performance under exposure to aggressive elements such as carbon dioxide and chlorides contribute as a drawback.
This thesis reports on a durability study on LWFC undertaken at Stellenbosch University (SU). LWFC beam specimens were exposed to cyclic wetting and drying periods using NaCl solution under controlled humidity and temperature conditions. The performance of two types of surface treatment agents in LWFC against preventing accelerated penetration of chloride ions and consequently chloride induced corrosion was the main focus. Chloride penetration was investigated by silver nitrate testing, and reinforcement corrosion was monitored via a non-destructive linear polarisation method using commercially available GECOR 10 corrosion rate measuring equipment.
The results indicated that inclusion of fly ash in reinforced LWFC reduces risk of dry shrinkage cracking, limiting localised corrosion on cracked locations. The surface applied silane-based water repellent treatment agent was effective in preventing moisture penetration, leading to the low reinforcement corrosion rates and chloride ion penetration depths.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar
Description
Thesis (MEng)--Stellenbosch University, 2018.
Keywords
UCTD, Chlorides -- Corrosion, Lightweight concrete --Service life, Concrete -- Expansion and contraction