Accession Number : ADA306699

Title :   Methods of Preparing Horizontal Construction Joints in Mass Concrete.

Descriptive Note : Final rept.,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS STRUCTURES LAB

Personal Author(s) : Neeley, Billy D. ; Poole, Toy S.

PDF Url : ADA306699

Report Date : FEB 1996

Pagination or Media Count : 82

Abstract : This report presents the results of a research program examining the effects of different methods of preparing horizontal construction joints in mass concrete construction. The purpose of the research program was to confirm existing guidance or, if necessary, update it. The joint cleaning procedures employed were (a) none, (b) high-pressure water cutting, (c) air-water cutting, and (d) air-water cutting to greater depth. The joint moisture conditions at the time of concrete placement were (a) continuously moist, (b) dry, and (c) dry and then remoistened. Jointed specimens were tested for direct tensil strength, shear strength, and permeability. The results indicated that good bond strengths are realized when horizontal construction joints are cleaned by high-pressure water cutting or by air-water cutting, and that undercutting coarse aggregate particles does not improve the strength of the joint. The results also indicated that better bond strengths are realized when the joint surface is allowed to dry approximately 24 hr immediately prior to placement of the next lift of concrete. Recommendations are made to consider revising current guidance to permit placement of concrete on a dry surface. No revisions to current guidance are recommended concerning joint cleaning procedures.

Descriptors :   *CONCRETE, *STRENGTH(MECHANICS), *BONDED JOINTS, TENSILE STRENGTH, PERMEABILITY, SURFACE ANALYSIS, GRAIN SIZE, SAND, MOISTURE CONTENT, FLY ASH, AGGREGATES(MATERIALS), EMPLACEMENT, HORIZONTAL ORIENTATION, CLEANING, FAILURE(MECHANICS), COMPRESSIVE STRENGTH, CONSTRUCTION MATERIALS, WATERTIGHTNESS, COHESION, CUTTING, SHEAR STRENGTH, PORTLAND CEMENT.

Subject Categories : Construction Equipment, Materials & Supplies
      Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE