Mechanical properties - Splitting tensile strength
The development of splitting
tensile strenght (EN 12350-6), measured at 0.5, 1, 2, 3, 7, and 28
days, of all concrete types is shown below as average of two
measurements at each age.
The trends observed are much the
same as what was evident for the development of compressive
strength. Among the Portland cement based concretes it is observed
that microsilica apparently increases strength development in the
middle period, i.e. particularly from 3 until 28 days of maturity.
There is no apparently "kick" in strength development from fly ash
at later ages. The slag based concretes exhibit a slow early
strength development followed by a period (2-28 days), where the
rate of strength gain is significantly higher compared to Portland
cement based concrete, before leveling off at a level higher than
any of the Portland cement based concretes. For the 3-powder
concretes lowering the w/c-ratio from 0.40 to 0.35 results in
higher strengths at all ages, while increasing the w/c-ratio from
0.40 to 0.45 results in lower strengths at early and late ages.