Section 4109 Revised 10172023.pdf

This is a technical specification document from the Iowa Department of Transportation (Iowa DOT) detailing aggregate gradation standards and requirements for concrete crushing operations. Section 4109 establishes definitions and specifications for coarse and fine aggregate particles, referencing gradation tables in the appendix for compliance standards. The specification addresses unacceptable materials, including those contaminated with organic or foreign substances, which may result in stockpile rejection at the Engineer's discretion. The document prohibits driving on Portland Cement Concrete (PCC) aggregate stockpiles as an unacceptable production practice and restricts the use of ramps used in stockpile construction from being certified as material, with ramp incorporation potentially resulting in complete stockpile rejection.

This technical specification directly supports the concrete crushing contract opportunity requiring contractors to crush approximately 1,176.98 tons of broken concrete to 3/4" Class A specifications (Gradation No. 11) across four Iowa DOT garage locations between July 1, 2025, and June 30, 2026. The specification ensures that crushed material meets Iowa DOT quality standards for aggregate production. Contractors must comply with these gradation requirements and handling protocols, including the removal of rebar and use of grizzlies to eliminate excess dirt and fines. For stockpiles exceeding 2,000 tons, quality control gradation reporting to District 1 Materials is mandatory, with the district conducting random verification gradations for acceptance.