compatibility of ultra high performance concrete as repair material

associated test results (temperature, slump, pressure air and unit weight) carried out rightafter mixing can be found in the Appendixes. Several compressive strength tests werecarried out with companion cylinders, 4x8 in, at different ages to assess the strength ofthe concrete. These compressive strength values are shown through Chapter 4.3.3 Experimental ProgramThe experimental program was carried out in two different steps. Firstly, the splittingtensile test was conducted. Once the results of this test were obtained, the slant-shear andpull off tests were designed. For this reason, there are some differences between thevariables studied in the splitting tensile test with respect to the slant-shear and pull offtests. These main differences are shown in Table 3.3:Table 3.3Different variables between the splitting tensile test and slant-shear and pull-off testsVariable Splitting tensile test Slant-shear and pull offtestsMoisture condition of theconcrete substrateConcrete surfacesAge of the compositesamplesBoth dry andsaturated conditionswere studiedSmooth, chipped,brushed, sandblastedand groovedLong term:185-298daysAll composite sampleswere cast on moisturesaturated concretesubstrateBrushed, sandblasted,grooved and roughShort term: 2-12 days3.3.1 Combination of Splitting Tensile Test with Freeze-Thaw CyclesTo assess how different surface treatments, substrate moisture conditions and freeze-thawcycles affect the splitting tensile bond strength, 90 composite and 14 monolithicspecimens were cast and tested. Table 3.4 lists the number of composite and monolithicspecimens assigned to each case study. The composite specimens, with a nominaldimension of 4x3x15.5 in, were made up of NSC and UHPC layers of 1.5 in each. Fourcomposite prisms were obtained from each beam for testing under indirect tension. Thistest was defined to study the bond strength in long-term performance since the age of the46