The inspector plays a vital role on every construction project ensuring that the completed operations comply with the owner’s plans and specifications. Recognizing that many agencies were inexperienced in doing chip seal, slurry seal or micro surfacing projects, and hesitant to add the treatment to their pavement management systems because of their lack of familiarity, the International Slurry Surfacing Association (ISSA) worked with the National Center for Pavement Preservation (NCPP) to develop a comprehensive page Inspector’s Manual for slurry systems including slurry seal/micro surfacing. A copy of the Inspector’s Manual can be obtained at www.slurry.org.
With Cape Seals, like most paving projects, the primary goal is to produce a strong, durable and aesthetically pleasing wearing surface for the traveling public. Some of the most important things inspectors can do to help achieve this goal are as follows:
Mix Design: Verify that a full mix design has been performed by a qualified lab, and that all test results meet or exceed the specified standards.
Quality Materials: Confirm that the aggregate, asphalt emulsion and other materials delivered to the job are in conformance with both the specifications and the materials used in the mix design. Best practices include sampling the delivered aggregate to confirm the gradation is within the stockpile tolerance limits. Also, periodically take a sample of the delivered emulsion/binder for testing.
Equipment Calibration: To ensure proper applicaton rates are placed in accordance with the chip seal mix design, the asphalt distributor and aggregate spreader must be calibrated. To ensure proper proportioning of the mix in accordance with the Job Mix Formula for slurry seal/micro surfacing, the paver must be calibrated for the emulsion, mineral filler, and the specific aggregate being used on the project. Comprehensive calibration information can be found in the Inspector’s Manual including sample calibration worksheets. Referencing the equipment manufacturer’s recommended calibration procedures will also simplify the calibration process rather than adapting to the universal procedure outlined in the Inspector’s Manual.
Surface Preparation: Walk or drive the entire pavement to be paved for the day to ensure the surface has been properly prepared.
Traffic Control: Verify the proper traffic control is in place to keep the traveling public safe and out of uncured materials.
Acceptable Weather: Measure the air and pavement temperature to determine if construction can start/continue.
Temperature, humidity and wind conditions all affect chip seal emulsion and slurry seal/micro surfacing break and cure times.
Quality Equipment: Verify the equipment for chip sealing (asphalt distributor and aggregate spreader) and slurry seal/micro surfacing (paver) is properly calibrated for the materials being used on the project, and the equipment is clean, well maintained, and free of any leaks. Ensure the spreader box and rubbers on the slurry seal/micro surfacing equipment are kept clean to avoid drag marks in the mat.
Quality Workmanship: For both treatments, ensure straight edge lines and quality joints (longitudinal and transverse). For slurry seal/micro surfacing, ensure there are no drag marks or blemishes in the mix. Verify the finished surface is uniform and consistent in terms of color and texture. For the chip seal, verify the finished surface is uniform and consistent in terms of binder and aggregate application rates.
Application Rates: Periodic checks should be made to verify that the amount of material being placed is in accordance with the specifications and appropriate for the gradation of the aggregate being used. For the chip seal portion, Spot checking the yield over a specific pavement area a few times each day is recommended. This can be done by strapping the distributor for binder and measuring rock lands for aggregate. For slurry seal/micro surfacing, spot checking the yield over a specific pavement area a few times each day using the calibrated counters on the paver is recommended. Other methods for tracking the amount of materials placed include keeping a list of the quantities of materials on each truck as they are placed, or tracking the quantities of all materials delivered to the project and deducting for waste.
Chip Seal Application Checklist: Provided by Federal Highway Administration (FHWA) and the Foundation for Pavement Preservation (FP2).
90-minute webinar on the Inspector’s Manual: highlighting key points of the Micro Surfacing inspector’s manual. (Provided by ISSA and the Asphalt Institute)
Slurry Seal Application Checklist: Provided by Federal Highway Administration (FHWA) and the Foundation for Pavement Preservation (FP2).
Micro Surfacing Application Checklist: Provided by Federal Highway Administration (FHWA) and the Foundation for Pavement Preservation (FP2).