High Performance Concrete Using Viscosity-Modifying Admixture

The use of viscosity modifYing admixture (VMA) has proved to be very effective in
stabilizing the rheological properties and consistency of self-compacting concrete (SCC).
SCC was developed in Japan in the late 1980s, and recently, this concrete has gained
wide use with a steadily increasing number of applications in many developed countries
such as Europe country and United States but not yet being utilized in Malaysia. SCC is
known for its excellent deformability, high resistance to segregation and use, without
applying vibration, in congested reinforced concrete structures characterized by difficult
casting condition. Identification or production of new low-cost VMA is then essential.
This paper presents the performance of local VMA supplied by one manufacturer in
enhancing the rheological and consistency properties of cement paste.
The study of the rheological properties and consistency of concrete to screen the
dosage of VMA to be used in SCC is a promising approach. Investigation was carried out
on concrete with VMA and HRWR to verify both admixtures' performance on
workability, segregation, filing ability with obstacles, compressive strength and porosity.
Besides, fresh and hardened concrete properties will be studied and mixes with various
dosage ofVMA to investigate the relationship between all properties.
The combined use of proper dosages of VMA and high-range water reducer
(HRWR) is shown clearly contribute to higher workability and lesser segregation. The
type of VMA and SP used in this study is Vismocrete and Adva that are provided by
same manufacturer. Different mix proportion of concrete under same condition must be
tested in order to obtain the optimum dosage for best result. Besides, the relationship
between fresh and hardened concrete properties were determined in this report.
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