Underhill Parking Lot ProjectCE165 ProjectGroup Membersz Danielle Lovez Ashley Takataz Laura Talbotz Jenna WongProject Backgroundz 1963 – Construction of original parking structure with a field on top levelz Early 1990s– Discovery of considerable damage to the post tension slabs z 1993 – Demolition of original structureProjectz Four levels of parking– 1,000 spots totalz Top level: turf sports field z General contractor: Overaa ConstructionCementz Modified Type II, also known as Permanente II/V Portland Cement– For cast-in-place concretez footings, rat-slabzType II– For cast-in-place concretez Parking and field slabsz Type I/II – Shotcretez WallsCement: Why This Type?– Moderate sulfate resistance– General use– Readily available– Cost effectiveAggregatez Cast-in-place– Sechelt (1” x #4) Sand: British Columbia– Sechelt Concrete Sand: British Columbia– Angel Island Sand: Bay Areaz Shotcrete– Concrete Sand: varies depending on availability– 3/8 gravel: varies depending on availabilityPozzolansz Fly Ash Type F– Improves workability– Decreases Porosityz Where was it used?– Footings– Rat Slab– WallsAdmixturesz Air Entrainmentz Water Reducingz AcceleratorsAir Entrainmentz Included in mix designz Unnecessary for local climatez Requires onsite testing – Time consuming– Additional specifications for usabilityz Eliminated need for AE from requirementsWater Reducingz Improve workabilityz Shotcrete– Grace Construction Productsz Cast-in-place– Master Builders Pozzolith 200NAcceleratorsz Used in Januaryz Why?– Cold Weatherz Benefits– Accelerated the hydration process – Allowed the formwork to be removed on timeMechanical Propertiesz Shotcrete– 28 day compressive strength of 4000 psiz Parking and field slabs– 56 day compressive strength of 5000 psi and 4000 psi respectivelyz Footings– 28 day compressive strength of 4000 psiPlacementz PumpingPumping…The Movie!Vibratingz Internal VibrationScreedingPurpose: Level the surface and remove excess concreteFloatingPurpose: Surface leveling and smoothing Power FloatingFloatingBroomingFinishing PatternsRoughened SurfaceSwirl PatternCuringz Sodium silicate curing compoundProblemsHoneycombingRain
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