Fresh properties, temperature rise and strength development of high strength concrete with binary and tertiary blended cements.
The use of high strength concrete in the construction industry has become more frequent
as both the knowledge of the behaviour of the material and the confidence in its
production have increased. An appropriate formulation of materials and mix proportions
can result in significantly enhanced performance such as high early strength, reduced heat
of hydration and increased durability. As a step towards obtaining optimum performance,
an investigation has been carried out on the fresh properties (workability), temperature
rise during hydration and strength development. This research was aimed at
understanding the role of supplementary cementing materials in binary (OPC+PFA,
GGBS, CSF) and ternary (OPC+ CSF/PFA, CSF/GGBS) combinations in these three
With respect to workability the use of binary mixes of PFA or CSF reduce the
superplasticiser dosage required to obtain a target slump, whereas GGBS increases it.
Optimum replacement levels of 10% CSF, 40%PFA+l0%CSF and 60%GGBS+l0% CSF
were found at a water/binder ratio of 0.26.
Binary mixes of 40% PFA or 60% GGBS reduce the peak semi-adiabatic temperature
rise compared to their equivalent OPC mix at 0.26 water/binder ratio. Ternary
combinations of 10% CSF with PFA or GGBS have shown significant reductions in peak
temperature rise compared to their equivalent binary mixes.
Measurement of the in-situ strength by temperature matched curing (TMC) has shown
higher early age strengths but lower long term strengths for both binary and ternary mixes
compared to cubes cured under standard conditions (20°C). Microstructural evaluation of
hardened cement paste indicates that these differences in strength are likely to be
associated with stresses generated at the paste/aggregate interface.
A novel non-destructive technique to assess the in-situ strength has shown good
correlation between conductivity and strength development of high strength concrete.