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Full-Depth Repairs
6.0 Performance
While full-depth repairs can be designed and constructed to provide good long-term performance (10 or more years), the performance of full-depth repairs on many in service pavements has been inconsistent. Causes of premature failures of full-depth repairs include inadequate design (particularly poor load transfer design), and poor construction quality. In addition, the effectiveness of some full-depth repair installations has been limited due to their placement on pavements that are too far deteriorated.
If properly designed and constructed, full-depth repairs can provide near-permanent rehabilitation of the distressed areas. Appropriate usage is very important to obtain desired performance. Important points for consideration in selecting this repair technique include the following:
- If the existing pavement is structurally deficient, or is nearing end of its fatigue life, a structural enhancement (such as an overlay) is needed to prevent continued cracking of the original pavement.
- If the deteriorations is widespread over the entire project length, an overlay or reconstruction may be more cost effective.
- If the original pavement has a severe material problem (Materials related distress), full-depth repairs may only provide temporary relief from roughness caused by spalling. Continued deterioration of the original pavement is likely to result in redevelopment of spalling and roughness.
- Additional joints introduced by full-depth repairs add to the pavement roughness, even if the pavement is diamond ground after the repairs are made.
- Nondeteriorated cracks in JPCP may be repaired by retrofitting dowels or tie bars in lieu of full-depth repair
The effectiveness of full-depth repairs depends strongly on the installation of the repairs at the appropriate time in the life of the pavement and on the proper design and installation of the load transfer system. The overall condition of the pavement and the extent of deterioration should be carefully examined to ensure that full-depth repairs will perform as intended.
7.0 Cost
The cost for full-depth repairs on jointed concrete pavements varies significantly, depending on the locality and site conditions (e.g., traffic). Typical recent costs in 2000 for 1.8 m (6 ft) repairs on a 250-mm(10 in) slab range from $60/m2 to $120/m2 ($50/yd2 to $100/yd2, with many falling between $78/m2 and $84/m2($65/yd2 and $80/yd2 ). Repair costs for CRCP are significantly higher.
Since the highest cost items for full-depth repairs are full-depth sawing and joints (including load transfer), the unit costs of repair can be reduced significantly when a larger area is involved. For example, typical recent costs in 2000 for 9-m (30-ft) slab replacements range from $54/m2 to $78/m2. ($45/yd2 and $80/yd2). The replacement of the entire slab is a more cost-effective solution than the placement of a series of smaller repairs within the same slab, and it is also more reliable.
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