SLIPFORM ULTRA-THIN OVERLAYS
FIELD TESTS HAVE SHOWN THAT CONCRETE MIXES CONTAINING FIBROUS STEEL REINFORCEMENT DEVELOP HIGH STRENGTH EVEN IN THIN OVERLAYS. FOR INSTANCE, A TYPICAL MIX HAS SHOWN A 24-HOUR FLEXURAL STRENGTH OF 645 PSI AND A 7-DAY STRENGTH OF 1100 PSI. A TYPICAL SPECIFICATION CALLS FOR 100,000-PSI TENSILE-STRENGTH LOW-CARBON ROLLED STEEL STOCK SLIT INTO FIBERS WITH A CROSS SECTION OF 0.022 BY 0.01 INCH. THE AMERICAN CONCRETE PAVING ASSOCIATION RECOMMENDS A LIMIT OF 2--2.5% FIBER BY VOLUME. THREE PROBLEMS THAT HAVE TO BE FACED IN USING FIBROUS STEEL ARE (1) SUPPLYING VERY LARGE AMOUNTS OF THE FIBERS FOR THE CONCRETE BATCHING PLANT, (2) KEEPING THE FIBERS FROM BALLING, AND (3) AVOIDING TEXTURING APPROACHES THAT DISTURB THE PARTICLES AT THE SLAB TOP. THE LATTER TWO PROBLEMS APPEAR TO HAVE BEEN SOLVED OVER THE PAST TWO SUMMERS OF TRIAL APPLICATIONS, BUT THE FIRST APPEARS TO ENTAIL VIBRATING AND GRIZZLIES AS AN ADD-ON. MAINLINE PAVING TESTS IN TAMPA AND DETROIT ARE DISCUSSED BRIEFLY. DURING THE SUMMER OF 1973 AN IOWA COUNTY HAS ARRANGED FOR A VARIETY OF MIXES AND PROCEDURES TO BE USED IN A 3-MILE OVERLAY JOB. IT IS NOTED THAT PARKING LOT PAVEMENTS HAVE BEEN SALVAGED USING FIBROUS CONCRETE PLACED WITH HAND TOOLS.
- Publication Date: 1973-4
Media Info
- Features: Photos;
- Pagination: p. 51-3
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Serial:
- Construction Equipment
- Volume: 47
- Issue Number: 4
Subject/Index Terms
- TRT Terms: Concrete pavements; Fiber reinforced concrete; Fibers; Overlays (Pavements); Reinforced concrete; Steel
- Subject Areas: Construction; Highways;
Filing Info
- Accession Number: 00215636
- Record Type: Publication
- Files: TRIS
- Created Date: Jun 19 1973 12:00AM