Building and Environment 41 (2006) 1124–1127
Production of high strength concrete by use of industrial by-products
Ramazan Demirbog
˘
a
Ã
,Ru
¨
stem Gu
¨
l
Civil Engineering Department, Engineering Faculty, Atatu
¨r
k University, 25240- Erzurum, Turkey
Received 10 January 2005; received in revised form 7 April 2005; accepted 19 April 2005
Abstract
Blast furnace slag aggregates (BFSA) were used to produce high-strength concretes (HSC). These concretes were made with total
cementitious material content of 460–610 kg/m
3
. Different water/cement ratios (0.30, 0.35, 0.40, 0.45 and 0.50) were used to carry
out 7- and 28-day compressive strength and other properties. Silica fume and a superplasticizer were used to improve BFSA
concretes. Slump was kept constant throughout this study. Ten percent silica fume was added as a replacement for ordinary
portland cement (OPC) in order to obtain HSC. The silica fume was used as highly effective micro-filler and pozzolanic admixture.
Superplasticizer at dosages of 2%, 1.5%, 1%, 0.5% and 0% by OPC weight for 0.30, 0.35, 0.40, 0.45 and 0.50 w/c ratios,
respectively, were adopted. Results showed that compressive strength of BFSA concretes were approximately 60–80% higher than
traditional (control) concretes for different w/c ratios. These concretes also had low absorption and high splitting tensile strength
values. It is concluded that BFSA, in combination with other supplementary cementitious materials, can be utilized in making high
strength concretes.
r 2005 Elsevier Ltd. All rights reserved.
Keyword: Blast furnace slag; Compressive strength; Water absorption; Splitting tensile strength
1. Introduction
There are many studies evaluating industrial by-
products in cement [1–5] as binder and aggregate [6–8] in
concrete industries.
The consumption of aggregates of all types has been
increasing in recent years in most countries at a rate far
exceeding that suggested by the growth rate of their
economy or of their construction industries. Artificially
manufactured aggregates are more expensive to produce
and the available source of natural aggregates may be at
a considerable distance from the point of use, in which
case the cost of transporting is a disadvantage. There are
however other factors to be considered. The continued
and expanding extraction of natural aggregate is
accompanied by serious environmental problems. Often
it leads to irremediable deterioration of the countryside.
Quarrying of aggregates leads to disturbed surface area,
etc., but the artificial aggregates from industrial wastes
are not only adding extra aggregate sources to the
natural and artificial aggregate but also prevent
environmental pollution. In the operation of a blast
furnace, the iron oxide ore is reduced to metallic iron by
means of coke, while the silica and alumina constituents
combine with lime (included in the furnace charge),
to form molten slag which collects on the surface
of the molten metal [9]. The slag issues from the furnace
as a molten stream at 1400–1600 1C. If this is allowed
to cool slowly, it solidifies to a gray, crystalline stony
material, known as ‘‘air-cooled slag’’, which is used
as base or sub-base for road beds and as an aggregate
for concrete [6].
With the development of concrete technology, high
strength concrete (HSC) up to 100 MPa and higher can
be reached without difficulties. According to the recent
International Federation for Structural Concrete (FIB)
HSC is defined as [10]: ‘‘All concrete with a compressive
cylinder strength above the present existing limits in
national codes, i.e., about 60 MPa and up to 130 MPa,
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doi:10.1016/j.buildenv.2005.04.023
Ã
Corresponding author. Tel: 90 442 2314768; fax: 90 442 236 0959
E-mail address: ramazan@atauni.edu.tr (R. Demirbog
˘
a).