RAPID SETTING CEMENT MORTARS FOR CONCRETE REPAIR

THE PURPOSE WAS TO DEVELOP AN ECONOMICAL RAPID SETTING CEMENT MORTAR FOR THE REPAIR OF CONCRETE BRIDGE DECKS AND ROADWAY WHICH COULD BE MIXED AND PLACE IN A MANNER SIMILAR TO ORDINARY PORTLAND CEMENT CONCRETE. THE FORMULATION IS BASED ON A COMBINATION OF TYPE II PORTLAND CEMENT, MOLDING PLASTER, FINE SAND, POWERED SAPONIFIED VINSOL RESIN AIR ENTRAINING AGENT, AND PLASTER RETARDER. IT IS BELIEVED THAT PERFORMANCE CAN BE IMPROVED BY THE USE OF PRESSURE CALCINED (HIGH STRENGTH) GYPSUMS IN PLACE OF THE MOLDING PLASTER AND BY THE ADDITION OF WATER REDUCER TO THE FORMULATION. THE DURABILITY OF RAPID SETTING MORTARS BASED ON A COMBINATION OF PORTLAND CEMENT AND GYPSUM MATERIALS IS LIMITED. A GOOD MORTAR OF THIS TYPE, PROPERLY MIXED AND PLACED, COULD BE EXPECTED TO LAST THREE TO FIVE YEARS UNDER TRAFFIC. THIS SHOULD BE CONSIDERED IF REPAIRS ARE PLANNED. SPECIFIC CONCLUSIONS REGARDING THE FORMULATION OF RAPID SETTING MORTARS BASED ON A COMBINATION OF PORTLAND CEMENT AND GYPSUM MATERIALS ARE (1) IN ORDER TO OBTAIN THE BEST DURABILITY, A SULFATE RESISTANT CEMENT MUST BE USED. (2) SET TIMES VARY CONSIDERABLY WITH DIFFERENT BRANDS AND DIFFERENT BATCHES OF THE SAME BRAND OF CEMENT. (3) ANHYDROUS CALCIUM SULFATE AND CALCIUM SULFATE HEMI-HYDRATE CAN BOTH BE USED TO ACCERATE THE SET OF PORTLAND CEMENT. (4) USE OF HIGH STRENGTH GYPSUM PLASTER RATHER THAN ORDINARY MOLDING PLASTER APPEARS TO OFFER SOME IMPROVEMENT IN DURABILITY OF THE RAPID SETTING MORTAR. (5) IN ORDER TO HAVE SUFFICIENT TIME FOR MIXING AND PLACING, A RAPID SETTING MORTAR SHOULD HAVE A MINIMUM INITIAL SET OF 15 MINUTES BY LABORATORY TEST. (6) ADDITION OF AIR ENTRAINING AGENT TO THE MIX IMPROVES WORKABILITY AND GIVES THE CURED MORTAR GOOD FREEZE-THAW RESISTANCE. (7) CONVENTIONAL CONCRETE WATER REDUCERS ARE NOT SUITABLE FOR USE IN THIS TYPE OF RAPID SETTING MORTAR. (8) GOOD CONCRETING PRACTICES SHOULD BE FOLLOWED AS CLOSELY AS POSSIBLE IN PLACING AND CURING RAPID SETTING CEMENT MORTARS. /AUTHOR/

  • Supplemental Notes:
    • 3-09-71-020
  • Corporate Authors:

    Texas State Department of Highways & Public Transp

    11th and Brazos Streets
    Austin, TX  USA  78701
  • Authors:
    • O'Connor, D L
  • Publication Date: 1971-6

Media Info

  • Features: Photos; References; Tables;
  • Pagination: 63 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00214137
  • Record Type: Publication
  • Files: TRIS, STATEDOT
  • Created Date: Jun 28 1972 12:00AM