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A trade-off concept for lightweight concrete in chloride environments

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conference contribution
posted on 12.01.2017, 11:00 by D. Dunne, M.D. Newlands, Christian Christodoulou, Chris GoodierChris Goodier
The aim of this study was to investigate the influence of supplementary cementing materials (SCM’s) on the initial surface absorption (ISA), sorptivity and chloride penetrability to ASTM C1202 and NT Build 492 of lightweight aggregate based concretes (LWAC), and to compare these properties to those of normal-weight aggregate based concretes (NWAC). The lightweight aggregate (LWA) was Lytag, a fly ash based aggregate, which was pelletised during manufacture. Three normal-weight aggregates (NWA) were investigated, including, natural river gravel, jurassic oolitic limestone and crushed dolomitic limestone. The SCM’s used were fly ash (FA), ground granulated blastfurnace slag (GGBS), limestone (LS), silica fume (SF), and metakaolin (MK). CEM I replacement was undertaken on a percentage mass basis. Experimental work focused on concrete mixes with a fixed water/binder ratio of 0.50 and a constant total binder content of 330kg/m3. 28-day results indicate that with respect to aggregate influence, for CEM I only concrete, reduced concrete performance is obtained when replacing normal-weight aggregate with lightweight on a like-for-like basis. These negative effects can be reduced however, by good cement addition specification, as was found in the majority of the concretes in this study. These benefits include, to varying degrees, enhanced compressive strength, and increased resistance to water permeation and chloride ion penetration. A trade-off between aggregate type and binder combination is therefore desirable, to enable enhanced concrete chloride ion resistance.

History

School

  • Architecture, Building and Civil Engineering

Published in

Performance-based approaches for concrete structures

Citation

DUNNE, D. ...et al., 2016. A trade-off concept for lightweight concrete in chloride environments. IN: Beushausen, H. (ed.). Performance-based approaches for concrete structures: Proceedings (fib SYMPOSIUM 2016), Cape Town, South Africa, 21-23rd November.

Publisher

© Federation internationale du beton

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

01/04/2016

Publication date

2016

Notes

This is a conference paper.

ISBN

9782883941229

Language

en

Location

cape town, south africa