Details are given of the preparation and installation of the slabs in a highway repair project completed in 1/24th the time required to cure fresh concrete. The slabs (0.67 ft prefab) were prepared in an open area 1500 ft from the repair zone. Top mat reinforcing steel of No. 4 rebars on 18 in. centers were used, with bottom mat formed by No. 4 bars on 12-in. centers. Lifting inserts were placed at points 1/6 span from the slab edges providing anchorage for lifting bolts and eyes. A 7.8 sack concrete mix with a 1-in maximum size aggregate and 0.4 percent Zeecon admixture was used for the slab, which was poured while Standard Beams were formed at the same time. Flexural tests were programmed and a 652 psi modulus of rupture developed at 6 days. The slabs were then ready for installation. By selecting off-peak traffic hours, a safe work area was provided for the crews. An Arrow Hydrahammer (diesel) shattered the concrete, which was placed in a haul truck by a Caterpillar 950 rubber-tired loader. Pavement removal and cleanup took 2.5 hours. The grout was then poured into the prepared bed prior to positioning the slabs over the area. A 5-6 inch slump, 7 sack, sand-cement grout was used and a previously prepared wooded screen struck off the grout at a point 0.01 ft high. The precast sections was carried into position and lowered by a 35-ton Lorain truck crane. Minimum handling was needed and the slabs moved easily into position. The cement finishers placed grout in the narrow work space between the slabs and existing pavement. Slabs were permitted to set for one hour. The 1-beam grade guides were then removed and the lane was ready to reopen to traffic. Total elapsed time was 7 hr. 15 min. and actual work time was 5 hr. 30 min. The total cost of the operation was $3000. The use of this technique provided increased safety and greatly decreased lane closure time.

Media Info

  • Features: Photos;
  • Pagination: p. 26-28
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00262426
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 13 1974 12:00AM