Loading...
Evaluation of mix specification and PFA as a cement replacer in concretes used in silage storage structures.
Citations
Altmetric:
Date
1999-09-01
Collections
Files
Loading...
eopr-4424.pdf
Adobe PDF, 266.71 KB
Research Projects
Organizational Units
Journal Issue
Citation
Lenehan, J.J., O'Kiely, P. Evaluation of mix specification and PFA as a cement replacer in concretes used in silage storage structures, End of Project Reports, Teagasc, 1999.
Abstract
At present,
concrete for silage storage structures is specified by the Irish Farm
Development Service (DAFF, 1992) in terms of a characteristic 28
day crushing strength of 40 N/mm2 and a minimum cement content
of 350 kg/m3. In addition, the maximum aggregate size used must
not exceed 20 mm and the slump of the unplasticised concrete
must not exceed 75 mm. There is no stipulation on the maximum
water to cement ratio to be used. This specification represents a
high strength concrete for agricultural use and has been upgraded
to this level in an attempt to improve the material’s resistance to
corrosion by silage effluent. A cement content of 350 kg/m3 is
regarded as a relatively high cement content and may promote
thermal cracking in the structures (Blackledge, 1990). This would
result in a concrete which would be more susceptible to attack by
corrosive effluent. A system of carrying out accelerated durability
tests on concrete specimens under controlled conditions has been
developed by Teagasc and University College Dublin (O’Donnell,
C., 1993). Trials carried out by O’Donnell, indicated that cement
content had little influence on the durability of concretes exposed
to silage effluent for the ranges of mixes examined, but the use of
excess water resulted in marked increases in deterioration. The
present study aims to further examine the effect of (i) cement content
and (ii) the use of PFA as a cement replacer.