Abstract: (10903 Views)
Abstract:Self-consolidating concrete (SCC) has been used increasingly over the last two decades,
especially in the pre-cast concrete industry because of its ability to consolidate without
vibration even in congested areas. The development of SCC mixture design has been driven
mostly by private companies who desired to utilize advantages of SCC. Consequently, there
exists limited public information regarding the performance of SCC mixtures. In addition,
SCC can be characterized as flowing concrete without segregation and bleeding, capable of
filling spaces and dense reinforcement. Further it should be able to flow through, and
completely fill the form without vibration. Due to the technical and economic advantages that
can be accrued by the use of pozzolans, they play an important role when added to Portland
cement by usually increasing the mechanical strength and durability of concrete structures.
This paper present, an experimental study on the properties of different self-consolidating
concrete mixes containing three types of pozzolanic materials in comparison with SCC
mixtures without any pozzolanic materials and conventionally vibrated concrete mixtures.
Silica fume, pumice powder and rice husk ash were used for both cement and filler
replacements. Various experiments such as slump-flow, J-ring, L-box, V-funnel and sieve
segregation resistance were investigated for fresh concrete. Further, compressive strength,
water and chloride-ion permeability and capillary water absorption at various days were
carried out to determine the properties of self-consolidating concretes.
The test results indicated that pozzolanic materials such as RHA and VP can be used to
produce SCCs. Regarding the strength properties, the test results showed that the 270-day
compressive strength of ordinary SCC is about 70 MPa, while SCC mixtures containing SF,
RHA and VP have strengths more than 90, 77 and 76 MPa, respectively. In addition, the
results proved that artificial and natural pozzolans enhanced the durability of SCC and
reduced the penetration, significantly. For instance, adding 15% pumice and 7% silica fume in
the SCC specimen reduced the water depth at 90 days by 19% and 54%, respectively.
Received: 2009/06/6 | Accepted: 2010/12/29 | Published: 2011/11/9