DateLaboratory Testing of Portland Cement Concrete Patch Material ...

Performance results reported by the California Department of Transportation (Caltrans)and the Minnesota Department of Transportation (Mn/DOT) indicate that concrete curingcompounds with resin composed of 100 percent poly-alphamethylstyrene show excellentwater retention (Vandenbossche, 1999). In fact, largely due to Mn/DOT's experience,WisDOT’s DBR warranty specification requires the use of a concrete curing compoundthat is a resin of 100 percent poly-alphamethylstyrene with a water loss of no more than0.08 lb/ft 2 (0.40 kg/m 2 ) in 72 hours.4.0 PROJECT OVERVIEWThis research study involved laboratory testing only; no field testing was conducted. Alltests were performed in an AASHTO accredited lab under the supervision of WisDOT’schief concrete engineer, Jim Parry.4.1 Standard Mn/DOT 3U18 Concrete MixThe control mix for this research study was based on the design for the Mn/DOT 3U18concrete mix. Mn/DOT uses a mix numbering system to classify concrete. The first digitdesignates the type of concrete (i.e. whether or not it includes an air entrainer), the seconddigit designates the grade of concrete (i.e. its design strength), the third digit designatesthe upper slump limit of the concrete, and the fourth digit designates the gradation rangeof the aggregate.As shown in Figure 3 on the following page, 3U18 concrete is designated as Type 3concrete (not to be confused with Type 3 cement), which means it contains an approved airentraining admixture to produce a specified air content of 4 to 7 percent. It is classified asGrade U concrete, so it has an anticipated compressive strength of 5600 psi at 28 days.The concrete is allowed a maximum slump of 1 inch and it is composed of coarseaggregate from Range 8. This aggregate gradation consists of the CA-80 coarseaggregate, which represents coarse aggregate sizes smaller than 3/8-inch. Although notdesignated in the mix numbering system, fine aggregate is also included in the 3U18 mix.8