compatibility of ultra high performance concrete as repair material

Figure 4.1 shows the mass variation of those composite samples subjected to 300 freezethawcycles. The slight increase between the two first measurements is due to the fact thatthe initial measure was taken in dry conditions while the specimens were saturated in thefollowing measurements. The slight variation between different samples is due to thedifferent thickness of the new and substrate layers. It can be stated that no spallingoccurred in the samples. Figure 4.2 shows the fundamental transverse frequencyevolution of these composite samples. As the weight variation, the initial increment wasdue to the saturation of the samples. It can be appreciated that the fundamental transversefrequency increased slightly with the exposure of the samples to the freeze-thaw cycles.This is explained due to continuation of the hydration as Misson (2008) stated in hisstudy of the UHPC performance under freeze-thaw cycling. The samples underwent anambient air curing regime and it is believed that they had abundant amounts ofunhydrated cement particles that could get hydrated in the presence of water. Graybeal(2006) also noted the gain in strength of UHPC during the freeze thaw process.Weight (grams)1716,51615,51514,5140 50 100 150 200 250 300Freeze-thaw cyclesGr 300 FT (1)Gr 300 FT (2)Gr 300 FT (3)Ch 300 FT (1)Ch 300 FT (2)Ch 300 FT (3)Br 300 FT (1)Br 300 FT (2)Br 300 FT (3)Sm 300 FT (1)Sm 300 FT (2)Sm 300 FT (3)Sb 300 FT (1)Sb 300 FT (2)Sb 300 FT (3)Figure 4.1 Weight of composite samples, cast in wetting conditions, subjected to 300 freeze-thaw cycles71