CURING PRESTRESSED CONCRETE BEAMS WITH ELECTRIC HEATING ELEMENTS

EXPERIMENTS HAVE BEEN CONDUCTED FOR CURING I-BEAM SECTIONS WITH ELECTRIC HEAT. THE INVESTIGATION INVOLVED CASTING AND CURING ELEVEN 8 TO 10 FEET LONG TEST SPECIMENS WHICH HAD 18 THERMOCOUPLES IMBEDDED WITHIN THE SECTION. FOUR MORE SENSORS WERE USED TO MEASURE EXTERNAL CONCRETE TEMPERATURE AND OTHERS TO RECORD AIR TEMPERATURE AND INTERNAL TEMPERATURE OF A TEST CYLINDER. A FIGURE ILLUSTRATES A TYPICAL TIME- TEMPERATURE CURVE. DURING THE RESEARCH, 72 TEST CYLINDERS WERE CAST AND CURED IN INSULATED BOXES WHICH CLOSELY SIMULATED ACTUAL CURING CONDITIONS OF THE GIRDER. TIME- TEMPERATURE CURVES ARE PRESENTED WHICH ILLUSTRATE THE CORRELATION BETWEEN VALUES FOR THE TEST CYLINDERS AND THOSE OF THE BEAM TAKEN AT HOLD DOWNS. THE SCHMIDT CONCRETE TEST HAMMER WAS USED TO TAKE REBOUND READINGS AT SEVERAL LOCATIONS OF KNOWN TEMPERATURE ON THE GIRDER. THE PROVISION OF THE ELECTRIC HEATING ELEMENTS FOR CURING IS DESCRIBED. TESTS WERE ALSO CONDUCTED ON 90- FOOT SECTIONS OF 50 I-BEAMS IN CITY AND COUNTRY. THE SUCCESS OF THE RESEARCH HAS LED TO THE APPROVAL BY STATE AUTHORITIES OF THE ELECTRIC HEAT METHOD OF CURING PRESTRESSED CONCRETE GIRDERS. THE ADVANTAGES OF THIS METHOD OVER OTHER CONVENTIONAL SYSTEMS ARE LISTED.

• Corporate Authors:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Kinder, W G
• Publication Date: 0

Media Info

• Features: Figures; Photos;
• Pagination: p. 70-5
• Serial:
  • Highway Focus
  • Volume: 4
  • Issue Number: 3

Subject/Index Terms

• TRT Terms: Beams; Casting; Concrete curing; Concrete tests; Electrical equipment; Girders; Heaters; I beams; Prestressed concrete; Prestressing; Rebound; Research; Temperature measurement; Testing; Thermocouples
• Old TRIS Terms: Electric heating elements
• Subject Areas: Construction; Highways; Research;

Filing Info

• Accession Number: 00215619
• Record Type: Publication
• Files: TRIS, USDOT
• Created Date: Jan 11 1974 12:00AM