Category:1106 Carbide-Tipped Snowplow Blades

The TowPLow, a snowplow able to clear two lanes of pavement with only one truck and one driver, is the brainchild of a MoDOT employee who applied his knowledge of farm equipment to snowplows. MoDOT then worked with a snowplow contractor to finetune the design and build the TowPLow. The TowPLow has been chosen to be a focus technology by the AASHTO's Technology Implementation Group and Missouri has been honored with the designation as a lead state in implementing the technology.

This article establishes procedures for inspecting, sampling and reporting carbide-tipped snowplow blades. The material specification requirements are set forth in the bid request issued by MoDOT.

1106.1 Apparatus

Rule with suitable graduations to accurately measure the material to be inspected.

1106.2 Procedure

Upon award of the contract for furnishing carbide-tipped snowplow blades, the Division Engineer, Materials, will determine the number and type of samples required for testing in the Laboratory. This determination will be made considering all blades on a statewide basis. The district(s) responsible for sampling will be notified by letter with a copy to all districts that are to receive blades.

1106.2.1 Inspection

All blades shall be inspected in each district for marking and fabrication compliance to include dimensions, placement of punchings, brazing of inserts, etc., as required by the specifications.

1106.2.2 Sampling

The inspector in the district(s) responsible for sampling shall obtain the requested number and type of samples and submit these samples to the Laboratory as directed in EPG 106.3.1.2 Submission of Laboratory Samples.

Upon completion of tests performed in the Laboratory, the samples will be returned to the district.

If the samples tested in the Laboratory fail to meet any of the specified requirements, resamples shall be obtained as directed by the Division Engineer, Construction and Materials.

1106.3 Report

If field inspection or Laboratory testing shows noncompliance with specification requirements, the AASHTOWARE Project (AWP) record shall be completed indicating that the material is rejected and the reasons for rejection shall be listed in the report.

If field inspection and Laboratory testing shows compliance with specification requirements the AASHTOWARE Project (AWP) record shall be completed indicating that the material is accepted. The record should include the statements that a satisfactory manufacturer's certification is on file and field inspection was satisfactory.

1106.4 Laboratory Testing Guidleines

This article establishes procedures for Laboratory testing and reporting samples of carbide-tipped snowplow blades. The material specification requirements are set forth in the bid request issued by MoDOT.

1106.4.1 Procedure

Tests consist of examination of punchings and dimensions, distortion, chemical analysis and brazing of the inserts for the blades, and hardness, density and percent cobalt for the tungsten carbide inserts.

Punchings, dimensions, distortion and brazing of the inserts shall comply with the requirements specified in the bid request.

Chemical analysis of the blades shall comply with the referenced ASTM Specification(s) specified in the bid request and tests shall be performed according to ASTM E30-70, exclusive of any later revisions thereto, using the following methods:

Carbon: Direct Combustion Method

Manganese: EPG 106.3.2.57 TM-57, Determination of Manganese and/or Copper in Steel

Phosphorus: Alkalimetric Method

Sulfur: Evolution Method

Silicon: Sulfuric Acid Method

Hardness, density and percent cobalt of the tungsten carbide inserts shall comply with the requirements specified in the bid request and tests shall be conducted according to the following methods:

Rockwell Hardness: ASTM B294, Rockwell A Scale

Density: ASTM B311

Percent Cobalt: EPG 106.3.2.21 TM-21, Determination of Cobalt in Tungsten Carbide Inserts

Original chemical test data and calculations shall be recorded in Laboratory workbooks. Physical and chemical test results shall be recorded through AWP.

Manufacturer's certification, as required in the bid request for carbide-tipped snowplow blades, shall be checked for specification compliance.

1106.4.2 Sample Record

The sample record shall be completed in AASHTOWARE Project (AWP) in accordance with AWP MA Sample Record, General, and shall indicate acceptance, qualified acceptance, or rejection. Appropriate remarks, as described in EPG 106.20 Reporting, are to be included in the remarks to clarify conditions of acceptance or rejection. Test results shall be reported on the appropriate templates under the Tests tab.