TY - GEN
T1 - A trade-off concept for lightweight concrete in chloride environments
AU - Dunne, David
AU - Newlands, Moray
AU - Christodoulou, Christian
AU - Goodier, Chris
N1 - Publisher Copyright:
© fédération internationale du béton (fib).
PY - 2016
Y1 - 2016
N2 - 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.
AB - 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.
KW - Chloride
KW - Durability
KW - Lightweight
KW - Normal-weight
KW - Supplementary cementing materials
KW - Trade-off
UR - http://www.scopus.com/inward/record.url?scp=85134833279&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85134833279
SN - 9782883941229
T3 - fib Symposium
SP - 1
EP - 10
BT - Fib Symposium 2016
A2 - Beushausen, Hans
PB - fib. The International Federation for Structural Concrete
T2 - International fib Symposium on Performance-Based Approaches for Concrete Structures, 2016
Y2 - 21 November 2016 through 23 November 2016
ER -