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The effect of different cements and pozzolans on chloride ingress into concrete

Johannesson, Björn LU (2000) In Report TVBM 3093.
Abstract
Chloride profiles were measured on ten different concrete qualities.

The effect of two different cements, an ordinary Portland cement,

OPC, and a sulfate-resistent Portland cement, SRPC, with and without

inclusion of silica fume and fly ash was investigated. The samples

were exposed to a 3 wt% sodium chloride solution for 119 days. Two

different preparations before exposure were studied. Both types of

preparations consisted of one-day membrane hardening after casting.

Af ter this a set of samples were dried for two we eks and then rewetted

in tap water for one week before exposure. The other set of samples

were stored in tap water one week before exposure to... (More)
Chloride profiles were measured on ten different concrete qualities.

The effect of two different cements, an ordinary Portland cement,

OPC, and a sulfate-resistent Portland cement, SRPC, with and without

inclusion of silica fume and fly ash was investigated. The samples

were exposed to a 3 wt% sodium chloride solution for 119 days. Two

different preparations before exposure were studied. Both types of

preparations consisted of one-day membrane hardening after casting.

Af ter this a set of samples were dried for two we eks and then rewetted

in tap water for one week before exposure. The other set of samples

were stored in tap water one week before exposure to chlorides. The

chloride content profile in concrete was measured by removing approximately

1.2 mm thick layers, from the exposed surface, by grinding.

The concrete powder, collected from different depths from the surface,

was dissolved in an acid and analyzed for chlorides by an ion-selective

electrode. The obtained chloride profiles were evaluated in two ways.

The first consisted of a simple curve fitting to the solution to Fick's

second law, without any special attention to boundary conditions, in

order to obtain the so-called effective diffusion constant. The other

method of evaluating the measured values consisted of a more detailed

hypothesis accounting for dielectrical effects, diffusion of free ions in

pore solution, and chemical reaction such as binding of chlorides and

dissolution of hydroxide from solid hydration products. Both methods

of evaluating the me asur ed data gave the result that the OPC

concretes resisted chloride ingress better than SRCP concretes at the

same water to binder ratios when stored in water before exposure.



The OPC concrete in which 5% of the cement content were replaced

by silica fume resisted chloride ingress significantly better than the

SRPC with the same relative amount of silica fume. This behavior

was independent of curing conditions. (Less)
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organization
publishing date
type
Book/Report
publication status
published
subject
in
Report TVBM
volume
3093
pages
62 pages
publisher
Division of Building Materials, LTH, Lund University
external identifiers
  • other:TVBM-3093
ISSN
0348-7911
language
English
LU publication?
yes
id
8d8df26e-7dec-48a7-9ad3-2c0c1793b6c7 (old id 1527381)
date added to LUP
2010-01-11 12:01:36
date last changed
2016-04-16 04:39:16
@techreport{8d8df26e-7dec-48a7-9ad3-2c0c1793b6c7,
  abstract     = {Chloride profiles were measured on ten different concrete qualities.<br/><br>
The effect of two different cements, an ordinary Portland cement,<br/><br>
OPC, and a sulfate-resistent Portland cement, SRPC, with and without<br/><br>
inclusion of silica fume and fly ash was investigated. The samples<br/><br>
were exposed to a 3 wt% sodium chloride solution for 119 days. Two<br/><br>
different preparations before exposure were studied. Both types of<br/><br>
preparations consisted of one-day membrane hardening after casting.<br/><br>
Af ter this a set of samples were dried for two we eks and then rewetted<br/><br>
in tap water for one week before exposure. The other set of samples<br/><br>
were stored in tap water one week before exposure to chlorides. The<br/><br>
chloride content profile in concrete was measured by removing approximately<br/><br>
1.2 mm thick layers, from the exposed surface, by grinding.<br/><br>
The concrete powder, collected from different depths from the surface,<br/><br>
was dissolved in an acid and analyzed for chlorides by an ion-selective<br/><br>
electrode. The obtained chloride profiles were evaluated in two ways.<br/><br>
The first consisted of a simple curve fitting to the solution to Fick's<br/><br>
second law, without any special attention to boundary conditions, in<br/><br>
order to obtain the so-called effective diffusion constant. The other<br/><br>
method of evaluating the measured values consisted of a more detailed<br/><br>
hypothesis accounting for dielectrical effects, diffusion of free ions in<br/><br>
pore solution, and chemical reaction such as binding of chlorides and<br/><br>
dissolution of hydroxide from solid hydration products. Both methods<br/><br>
of evaluating the me asur ed data gave the result that the OPC<br/><br>
concretes resisted chloride ingress better than SRCP concretes at the<br/><br>
same water to binder ratios when stored in water before exposure.<br/><br>
<br/><br>
The OPC concrete in which 5% of the cement content were replaced<br/><br>
by silica fume resisted chloride ingress significantly better than the<br/><br>
SRPC with the same relative amount of silica fume. This behavior<br/><br>
was independent of curing conditions.},
  author       = {Johannesson, Björn},
  institution  = {Division of Building Materials, LTH, Lund University},
  issn         = {0348-7911},
  language     = {eng},
  pages        = {62},
  series       = {Report TVBM},
  title        = {The effect of different cements and pozzolans on chloride ingress into concrete},
  volume       = {3093},
  year         = {2000},
}