USE OF LIMESTONE DUST FOR CONCRETE IN XAYABURI HYDROELECTRIC POWER PROJECT

Abstract

The Xayaburi Hydroelectric Power Project is a huge concrete structure
project which needs more than 4 million cubic meter of concrete. At peak
period, the concrete consumption went higher than 150,000 cubic meter per
month. The project located in remote area and limited with river sand
source. In addition, the river sand is too fine. This article aims to present
achievement on utilization of manufactured sand with limestone dust for
concrete works. The coarse and sharp manufactured sand has mixed with
fine and round river sand resulted well gradation fine aggregate. Anyhow,
the manufactured sand composes of limestone dust higher than prescribed in
ASTM C33 and the project specification. The washing method has been
used to reduce limestone dust to meet the Standard. In contrast, the resulted
of washing method had shown in adequate production rate, gap gradation,
time consume and compose with additional cost. In order to utilize all
manufactured sand, without washing, the physical and chemical properties
of limestone dust have been researched. The resulted shown that the
limestone dust equivalent as sand. Then, the concrete trial mix was
undertaken. As a result, the concrete properties were in the range of required
compressive strength, well pump ability, well water consumption. As of
present, concrete classes 25, 35 and 50 MPa, self-compacted concrete,
Roller Compacted Concrete, Precast Concrete, Backfill Concrete, Silica
fume concrete produced from the manufactured sand with high fine content
have been adopted without any defect in the concrete quality.