compatibility of ultra high performance concrete as repair material

As shown in the above tables, the macrotexture depth and ICRI profile results weresimilar in the brushed and sandblasted surfaces for all splitting tensile, slant shear andpull off samples. The introduction of the retarder concrete method proved to be effectivein obtaining a rough surface.3.6 Placing overlay materialThe main difference between placing UHPC on the concrete substrate between thesplitting tensile test and pull off and slant shear tests is that in the indirect tensile test,both dry and saturated conditions for the concrete substrate were used while for the pulloff and slant shear tests, the saturated condition for the concrete substrate was alwaysused. This is due to the fact that the initial splitting tensile results showed higher bondstrength in saturated conditions than in dry conditions.3.6.1 Combination of Splitting Tensile Test with Freeze-Thaw CyclesAs previously mentioned, two different moisture conditions were used. Dry concretesubstrate is considered as the concrete substrate that was kept in environmentalconditions for a period longer than 28 days. Saturated concrete substrate is defined as theconcrete substrate that was submerged in a water tank for a period of at least 24 hours,and then covered by a damp cloth to keep the moisture until placing the overlay material,as shown in Figure 3.15. The surface was wet, however with no free water on it. UHPCwas placed into the moulds by putting it in one corner and allowing it to flow into themould. Vibration for 5-10 seconds was applied once UHPC was filling most parts of themould. After pouring the overlay material, the composite specimens were covered byplastic sheets for three days before demoulding.60