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Best Practices Guide. DRAFT Soliciting Comments for 30 Days As lab testing moves forward Changes in limits may be fine tuned As field work moves forward Construction procedures will be amended Casting sequence may be changed. Goals. Tools for Engineers and Contractors
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Best Practices Guide • DRAFT • Soliciting Comments for 30 Days • As lab testing moves forward • Changes in limits may be fine tuned • As field work moves forward • Construction procedures will be amended • Casting sequence may be changed
Goals • Tools for Engineers and Contractors • Design Aides (hard copy and web based) • Durable Bridge Decks and Other Structures • Reduced Life-Cycle Cost • Longer Span Options with High Strength Concrete
Major Restraint Moderate Continuous spans Girder Size Girder type Deck Thickness Alignment of rebars Design Factors affecting Cracking
Major Heat of Hydration Cement Content/Type Aggregate Type Modulus of Elasticity Creep Coefficient Moderate Coefficient of Thermal Expansion Paste Volume W/cm ratio Deck Thickness Silica Fume Material Factors Affecting Cracking
Major Weather Time of Casting Moderate Curing period Curing measures Finishing procedures Construction Factors Affecting Cracking
QC/QA – before casting • Planning, time scheduling, assignments • Material selection and maintaining quality • Inspection of batch plant and trucks • Qualification of employees (certification) • Mixture designs to optimize only needed properties
QC/QA – during casting • Planning, time scheduling, assignments • Timely transport and delivery • Fresh concrete testing • Qualification of employees (certification) • Verification of mixture design • Continuous casting • Minimize Finishing • Curing measures immediately following placement
QC/QA – after casting • Planning, time scheduling, assignments • Maintenance of curing measures • Hardened concrete testing • Qualification of employees (certification) • Monitor in-situ strength gain (maturity) • Periodic evaluation for repair, rehab, or replacement.
Review and Comments • Provide comments by mid June • Second Draft will come out on the web in late June • www.engr.psu.edu/ce/I-99hpc