FIELD PRACTICES IN CONCRETE PUMPING

DESIGNED TO PROVIDE CURRENT TECHNICAL INFORMATION TO PRODUCERS AND USERS OF READY-MIXED CONCRETE, THIS PUBLICATION DISCUSSES THE BASICS OF CONCRETE PUMPING AND OFFERS GUIDELINES TO AVOID MANY PROBLEMS OFTEN ASSOCIATED WITH CONCRETE PUMPING. THE OBSERVATION IS MADE THAT THE KEY TO A SUCCESSFUL PUMPING JOB IS CLOSE COOPERATION BETWEEN THE CONTRACTOR, PUMPER AND THE READY-MIXED CONCRETE PRODUCER. THE COMBINED GRADATION OF THE AGGREGATES IS ONE OF THE MOST IMPORTANT FEATURES. A GOOD AGGREGATE FOR PUMPING IS ONLY USEFUL IF ITS GRADING IS COMPLEMENTED BY THE COARSE AGGREGATE. GRADING RECOMMENDATIONS DEVELOPED FOR FINE AGGREGATE ARE ILLUSTRATED IN FIGURES. ATTENTION SHOULD BE PAID TO THE PERCENTAGE PASSING THE NO. 50 AND THE NO. 100 SCREENS. THIS MATERIAL ALONG WITH SUFFICIENT CEMENT IS ESSENTIAL FOR PUMPABILITY. THE ACI 304 RECOMMENDS 15 PERCENT PASSING THE NO. 50 SCREEN AND 5 TO 10 PERCENT PASSING THE NO. 100 SCREEN. CONSIDERATION IS GIVEN TO THE SLURRY SEAL. THE SPECIFICATIONS FOR CONCRETE CONSTRUCTION WHICH PROVIDE A TABLE OF EMPIRICAL VALUES TO ESTABLISH THE UNIT VOLUME OF COARSE AGGREGATE BASED ON THE TOPSIZE AND THE FM OF THE SAND TO BE USED, ARE DISCUSSED. WHEN CONCRETE IS PUMPED THROUGH A REDUCING SECTION IT MUST CONFORM TO THE CHANGING DIMENSIONS, AND THE LENGTH OF THE REDUCER DETERMINES HOW FAST THIS ACTION MUST TAKE PLACE. REDUCERS SHOULD BE AS LONG AS POSSIBLE, NOT ONLY TO MAKE IT EASIER FOR THE CONCRETE TO RESHAPE TO THE SMALLER DIMENSION BUT TO REDUCE PUMPING PRESSURES. COARSER MIXES CAN BE PUMPED MORE SUCCESSFULLY AT LOW SLUMPS OF ABOUT 3 INCHES. LARGER LINE DIAMETERS ENABLE THE PUMPING OF LARGER AGGREGATE OR SMALLER AGGREGATE MORE EASILY. AT A CONSTANT LINE VELOCITY OF 4 FEET PER SECOND, A 4 INCH LINE DELIVERS 48 CUBIC YARDS PER HOUR, WHEREAS A 5 INCH LINE DELIVERS OVER 70 CUBIC YARDS PER HOUR. THE ROLE OF THE READY MIX PRODUCER, AND THE PROBLEM OF SAFETY ARE OTHER ASPECTS DISCUSSED.

  • Supplemental Notes:
    • NRMCA PUB NO 142
  • Corporate Authors:

    Nat Ready Mixed Concrete Association

    ,    
  • Authors:
    • O'Donnell, W
  • Publication Date: 1973-3

Media Info

  • Features: Figures;
  • Pagination: 16 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00214264
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 20 1974 12:00AM