CONTROL OF MIXING WATER CONTENT AND
DURABILITY OF CONCRETE
31st Our World in Concrete and Structures (OWICs) - 2006
R. Sakurada*, Akita National College of Technology, Japan
Y. Kawazoe, Tohoku University, Japan
mixing water content, ready-mixed concrete, durability, chloride diffusion
This paper describes that the effect of extra mixing water content on concrete durability,
especially on resistance to chloride penetration, is numerically analyzed. In the field
observations, the change in surface moisture of stockpiled sands was monitored in concrete plant, and the measured value of mixing water content was compared with the
desired-amount of mixing water in specified mix. The chloride contents were numerically
calculated for Portland cement concrete and blast furnace slag cement concrete based on an assumption of extra mixing water content.
10 % increase in extra mixing water content of Portland cement concrete with water to
cement ratio of 0.705 induces 26 % increase in chloride diffusion coefficient. Then 20 %
increase in extra mixing water content dramatically extends the chloride diffusion coefficient in 45 %. The increasing rate of chloride diffusion coefficient due to extra mixing water content for blast furnace slag cement concrete, however, is slightly lower than that for Portland cement concrete.