DISCUSSION OF REPORT OF COMMITTEE ON CHARACTER AND USE OF ROAD MATERIALS. I. CONCRETE MATERIALS

THE IMPORTANCE OF THE WATER-CEMENT RATIO IS EMPHASIZED. THE STRENGTH AMD MANY OTHER PROPERTIES DEPENDS ON THE RATIO OF WATER TO CEMENT SO LONG AS THE CONCRETE IS PLASTIC OR WORKABLE. A SPECIFICATION WAS USED ON A NUMBER OF IMPORTANT JOBS WHICH IS BASED ALMOST ENTIRELY ON THE ADEQUATE CONTROL OF THE QUANTITY OF MIXING WATER. WHERE CONCRETE OF GREATER WORKABILITY IS REQUIRED, IT IS PRODUCED BY REDUCING THE QUANTITY OF AGGREGATES RATHER THAN BY INCREASING THE QUANTITY OF MIXING WATER AS WAS ORDINARILY DONE UNDER THE OLDER PRACTICE. CONCRETE WHICH WILL GIVE A COMPRESSIVE STRENGTH OF 2,500 POUNDS OR MORE AT THREE DAYS CAN NOW BE READILY PRODUCED. THREE TENDENCIES WERE NOTABLE DURING THE PAST FEW YEARS WITH REFERENCE TO THE REQUIREMENTS OF AGGREGATES FOR CONCRETE ROADS: (1) ACCEPTANCE OF AGGREGATES OF LOWER HARDNESS OF TOUGHNESS, (2) SPECIFYING AGGREGATE OF LARGER SIZE, AND (3) INSISTENCE ON UNIFORMITY OF SIZE AND GRADING. THE SODIUM SULFATE TEST WAS APPLIED TO CONCRETE AGGREGATES BY A NUMBER OF DIFFERENT INVESTIGATORS. FURTHER STUDY SHOULD BE GIVEN TO THIS TYPE OF TEST AND ITS RELATION TO NATURAL FREEZING AND THAWING. IN TESTS OF AGGREGATES OR RESEARCHES INVOLVING AGGREGATE, EXTREME CARE MUST BE USED IN SECURING PROPER SAMPLES. FIELD INVESTIGATIONS ON CONCRETE BLOCKS EXPOSED TO HIGHLY CONCENTRATED SULFATE SOILS AND WATERS SHOW A REMARKABLE CORRELATION BETWEEN THE RESISTANCE OF CONCRETE TO SULFATE AND ITS COMPRESSIVE STRENGTH AT 28 DAYS. FACTORS SUCH AS REDUCED WATER-CEMENT RATIO, INCREASED QUANTITY OF CEMENT, BETTER GRADING OF AGGREGATES, MORE SATISFACTORY CURING, ETC. WHICH GAVE CONCRETE OF HIGHER STRENGTH ALSO GAVE A BETTER RESISTANCE TO SULFATE ACTION.

  • Supplemental Notes:
    • Vol 6, pp 258-260
  • Authors:
    • Abrams, D A
  • Publication Date: 1927

Media Info

  • Monograph Title: Proceedings of the Sixth Annual Meeting of the Highway Research Board Held at Washington, D.C., December 2-3, 1926
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00213733
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 2 1971 12:00AM