ABSTRACT
This paper presents the research results of mixture on a new non-dispersive con
crete admixture for use in underwater concrete. Physical and mechanical proper
ties and durability of the concrete in fresh and hardened were investigated, and ap
plications of the concrete in two underwater repair projects were introduced.Test
results showed that the dispersed cement paste is only 6% ~ 16% of control when
the concrete poured in underwater, compressive strength ratio of the concrete in
underwater to in air reached 83% and over. There are marked improvement in
other mechanical properties and durability in contrast to control, furthermore, ex-
cellent workability such as no bleeding and never segregation, self-flowability
and self-compaction.