Supervisor/Foreman
Fatigue Cracking
Description Series of interconnected cracks caused by fatigue failure of the HMA surface (or stabilized base) under repeated traffic loading. In thin pavements, cracking initiates at the bottom of the HMA layer where the tensile stress is the highest then propagates to the surface as one or more longitudinal cracks. This is commonly referred to … Read more
Non-Uniform Texture
Description Differences in appearance within the mat surface. Extreme differences in mat surface appearance often take on the look of tearing or streaking and should be investigated as such. Typically, mat areas that look rougher and more coarse than other areas are of the greatest concern. HMA mixtures with larger nominal maximum aggregate sizes will … Read more
Shrinkage Cracking
Description Hairline cracks formed during PCC setting and curing that are not located at joints. Usually, they do not extend through the entire depth of the slab. Shrinkage cracks are considered a distress if they occur in an uncontrolled manner (e.g., at locations outside of contraction joints in JPCP or too close together in CRCP). … Read more
Jointed Reinforced Concrete Pavement
Jointed reinforced concrete pavement (JRCP, see Figure 1) uses contraction joints and reinforcing steel to control cracking. Transverse joint spacing is longer than that for JPCP and typically ranges from about 7.6 m (25 ft.) to 15.2 m (50 ft.). Temperature and moisture stresses are expected to cause cracking between joints, hence reinforcing steel or … Read more
Subgrade Preparation for New Pavements
The overall strength and performance of a pavement is dependent not only upon its design (including both mix design and structural design) but also on the load-bearing capacity of the subgrade soil. Thus, anything that can be done to increase the load-bearing capacity (or structural support) of the subgrade soil will most likely improve the … Read more
Compaction
Compaction is the process by which the volume of air in an HMA mixture is reduced by using external forces to reorient the constituent aggregate particles into a more closely spaced arrangement. This reduction of air volume produces a corresponding increase in HMA density (Roberts et al., 1996[1]). Compaction is the greatest determining factor in … Read more
Longitudinal Joint Construction
A longitudinal joint is the interface between two adjacent and parallel HMA mats. Improperly constructed longitudinal joints can cause premature deterioration of multilane HMA pavements in the form of cracking and raveling (Figures 1 and 2). These distresses, caused by relatively low density (high air voids) and surface irregularity at the joints, can largely be … Read more
Pumping
Description Movement of material underneath the slab or ejection of material from underneath the slab as a result of water pressure. Water accumulated underneath a PCC slab will pressurize when the slab deflects under load. This pressurized water can do one of the following: Move about under the slab. Move from underneath one slab to … Read more
Punchout
Description Localized slab portion broken into several pieces. Typically a concern only with CRCP. Problem Roughness, allows moisture infiltration leading to erosion of base/subbase support, cracks will spall and disintegrate. Possible Causes Can indicate a localized construction defect such as inadequate consolidation. In CRCP, it can be caused by steel corrosion, inadequate amount of steel, … Read more
Linear Cracking
Description Linear cracks not associated with corner breaks or blowups that extend across the entire slab. Typically, these cracks divide an individual slab into two to four pieces. Often referred to as “panel cracking”. Problem Roughness, allows moisture infiltration leading to erosion of base/subbase support, cracks will eventually spall and disintegrate if not sealed Possible … Read more
Sponsors
