compatibility of ultra high performance concrete as repair material
compatibility of ultra high performance concrete as repair material
compatibility of ultra high performance concrete as repair material
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average <strong>of</strong> these values. The flow me<strong>as</strong>urements after 20 blows w<strong>as</strong> between 7.9-9.8 in(200-250 mm) for all UHPC mixes c<strong>as</strong>t. Lafarge North America (2003) defines this range<strong>as</strong> fluid mixture. Besides this control test, cylinders, 3x6 in, were c<strong>as</strong>t and tested undercompression from each UHPC mix done. The cylinders were demould at 3 days afterc<strong>as</strong>ting and were exposed to ambient conditions until the day <strong>of</strong> testing. These values areshown throughout Chapter 4.3.2.2 NSC mixingNSC mixes were designed to satisfy the requirements given by Michigan Department <strong>of</strong>Transportation (2009). These requirements consist <strong>of</strong>:• 28-day compressive strength greater than 4500 psi (31 MPa)• minimum cement content <strong>of</strong> 657 lb/yd 3 (390 kg/m 3 )• an entrained air <strong>of</strong> 4.5±1.5 %• slump between 1 and 6 in (25–150 mm)The cement content <strong>of</strong> the NSC mix w<strong>as</strong> 664 lb/yd 3 (394 kg/m 3 ). The seven mixes <strong>of</strong>conventional <strong>concrete</strong> met the requirements previously mentioned except one mix thatexceeded slightly the slump value (6.5 in) and another that surp<strong>as</strong>sed the entrained air(6.4%); therefore, it can be stated that the <strong>concrete</strong> substrate <strong>of</strong> the samples for thesplitting tensile, slant shear and pull <strong>of</strong>f tests accomplish with the MDOT specified mixrequirements. Fine and coarse aggregate met the requirements <strong>of</strong> section 902 <strong>of</strong> theMDOT 1996 Standard Specification for Construction (Michigan Department <strong>of</strong>Transportation 1996). The maximum size for the coarse aggregate used in the NSC mixesfor the splitting tensile test w<strong>as</strong> ½ in to avoid compaction problems while the NSCaggregate size for the slant-shear and pull-<strong>of</strong>f samples w<strong>as</strong> 1 in. The coarse aggregatedistribution w<strong>as</strong> according to size number 7 for the splitting tensile samples and to sizenumber 67 for the slant shear and pull <strong>of</strong>f samples, specified in ASTM C33 (StandardSpecification for Concrete Aggregates).Information regarding the design <strong>of</strong> the four NSC mixes used to c<strong>as</strong>t all splitting tensilesamples and the three NSC mixes for the slant-shear and pull-<strong>of</strong>f samples, along with45
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