Comal County Chip Sealing June 26, 2007

Chip sealing is the application of a bituminous binder immediately followed by the application of an aggregate. The aggregate is then rolled to embed it into the binder. Binder ApplicationAggregate Application Rolled

Advantages of Chip Sealing Improved Skid Resistance Cost Effective Treatments Good Durability (Typically 5-7 Years) Ease of Construction Chip Seal = 1 Mile/Day Asphalt = 1 Mile/Week

Disadvantages of Chip Sealing Flying Chips – Broken windshields and vehicle damage Noise Considerations – Chip seals can be noisy to travel on Weather Considerations – Must be constructed during warm, dry weather during daytime only Pedestrian – Not good for roller-blading & skateboarding

Materials Binders must provide good adhesion, or stickiness Aggregates must have following characteristics: Single-sized, if possible Clean Angular (not rounded) Aggregates must be damp for emulsion use

Construction Process Surface Preparation Crack Sealing or Filling of Cracks Patching Deteriorated Areas Cleaning or Brooming Any Loose Material Removing Pavement Markers and Delineators

Construction Process Binder Application Uniformly Apply the Binder Over the Surface at a Designed Rate Pavement Surface Temperature Should be 55ºF and Rising Humidity Should be 50% or Lower Most Important Step in Process

Construction Process Aggregate Application Should Follow the Binder Application by no more than 90 Seconds Should be no more than 100 Feet Behind Distributor Truck

Construction Process Aggregate Application Should Follow the Binder Application by no more than 90 Seconds Should be no more than 100 Feet Behind Distributor Truck

Construction Process Rolling Initial Rolling by Pneumatic Roller or Steel Rollers Compaction by Traffic Finishes the Process Should be Done During Hotter Weather Should Follow Aggregate Spreading by no more than 500 Feet Minimum of Two Rollers Should be Used to Cover the Full Width of the Chip Spreader

Construction Process Brooming After Chip Seal, Excess Aggregate Must be Broomed Off Within 2 to 4 Hours after Sealing

Possible Problems Bleeding – Too much binder leading to “leaking” of emulsion Traffic Control – Ensure that vehicles do not drive on binder application “Shelling” – Aggregate not applied in a timely manner. Binder sets. Aggregate does not stay in place.

Comal County Canyon Lake Spillway Canyon June 26, 2007

1998 Storm Totals Storm Total for 1998

Storm Total for 2002

Structural Flood Control Measures in Comal County Canyon Reservoir

Structural Flood Control Measures in Comal County Emergency Spillway

Structural Flood Control Measures in Comal County x