compatibility of ultra high performance concrete as repair material

The equipment used in the surface preparation is shown in Figure 3.8. A steel brush wasemployed to remove the dust on the surface and the chipped surface was obtained byusing a steel drill-bit. The saw was used to make the grooves in the slabs, and asandblasting equipment was utilized to attain the sandblasted surface.(a) Cordless Drillwith a metallicbrush and a drillbit.(b) Saw to makethe grooves.Figure 3.8 Equipment for the surface treatment(c) Sandblastingequipment (outsideview).(d) Sandblastingequipment(inside view).3.4.2 Slant shear testThree different NSC mixes were made to cast all composite prisms. The compositeprisms were 3.5x3.5x14 in, fitting in the size range used by other researches andpreviously described in 3.1.2. These dimensions are large enough to allow castingconcrete substrate contrasting ASTM C 882 that use mortar substrate. Different methodscan be used to obtain the inclined surface in the concrete substrate. ASTM C 882recommends the use of dummy sections that are made up of epoxy-resin mortar, fit themold, and are equal to half the volume of the specimen with an angle of 30° fromvertical. In a similar way, Climaco and Regan (2001) utilized oiled wooden inserts intheir steel beam molds to form the slant surfaces in the substrate. Abu-Tair et al. (1996)and BS EN 12615:1999 (British Standard 1999) cast concrete prisms and later cut them at30° to the vertical. The constructive process chosen for this research consisted of workingwith wooden inserts in timber molds to obtain an inclined surface, as shown in Figure3.9.53