The Iowa Department of Transportation (DOT) has established a Quality Assurance Program (IM 205) to assure that the quality of materials and construction workmanship incorporated into all highway construction projects is in reasonable conformity with the requirements of the approved plans and Specifications, including approved changes. It consists of an Acceptance Program and an Independent Assurance Program (IAP), both of which are based on test results obtained by qualified persons and equipment.


The acceptance portion of the program covers quality control (QC) sampling and testing and verification sampling and testing. The IAP portion of the program covers the evaluation of all sampling and testing procedures, personnel, and equipment used as part of an acceptance decision (includes contractor, contracting agency, and consultant).



To fulfill the materials acceptance requirements, several methods are used by the DOT.


Sampling & Testing (Test Report)


Approved Brands

Approved Sources

Approved Shop Drawings

Approved Catalog Cut

Inspection Report

Visual Approval by the Engineer


The Instructional Memorandum IM 204 Appendices A through W contain the material acceptance information for the type of work being done.  If there is a conflict in wording between the appendix and another Instructional Memorandum or appendix Z, the appendix A through W will supersede the others.


In many cases more than one method may be required for acceptance in the 204 Appendices and tables in the back of this guide. For some new or special materials, the District Materials Engineer may need to determine the most appropriate acceptance requirements.

In order to provide the Contractor the opportunity to construct a project with minimal sampling and testing delays, inspection is performed at the source for many materials. Source inspection may consist of inspecting process control, sampling for laboratory testing or a combination of these procedures. All source-inspected or certified materials are subject to inspection at the project site prior to being incorporated into the work. Project site inspections are for identification of materials with test reports and for any unusual alterations of the characteristics of the material due to handling or other causes. Verification samples secured by project agency personnel of source-inspected, certified, or project processed materials are also required for some materials in order to secure satisfactory validation for acceptance.


When certification procedures are required, the Contractor may, on the Contractor’s own responsibility and at the Contractor’s risk, incorporate these materials into the work. Acceptance will be based on satisfactory certification and compliance of the test results of any verification samples. When verification samples are not taken, acceptance will be based on satisfactory certification.



When a material is sampled and tested, the results will be documented on a construction form or a test report. There is quality control sampling and testing done by the Contractor or producer and verification sampling testing done by the Project Engineer, the District Materials Engineer, the Central Materials Laboratory, or an independent laboratory.


In many cases, in addition to sampling and testing, some other type of acceptance method will also be required. Sampling and testing may be done at the project, supplier, or source depending on which is the most appropriate.



For many materials, a fabricator, manufacturer, or supplier is required to provide the Project Engineer with a certification document stating that the material meets the requirements of the plans and specifications. In most cases, the fabricator, manufacturer, or supplier must also be on an approved list in the Materials Approved Products Listing Enterprise (MAPLE).  For some of these materials, sampling and testing is also required before final acceptance. The certification comes in a variety of forms:


·        Stamped or preprinted on truck tickets as with aggregates,


·        Stamped or preprinted on invoices as with Portland Cement and asphalt binder,


·        Stamped or printed on the Mill Analysis as with reinforcing steel, structural steel, and other metals,


·        Furnished as a separate document with each shipment as with zinc-silicate paint, engineering fabrics, epoxy coatings, and dowel baskets,


·        Stamped or printed on a list of materials for each shipment as with CMP, concrete pipe, and corrugated plastic subdrain,


The inspector will verify that the certification has been entered into DocExpress.



 (May also be referred to as “Approved Producer, Approved Supplier, Approved Fabricator, or Approved Brand”) The source, producer, and the material must be evaluated and approved by the Office of Construction and Materials according to the appropriate Materials IM in order to be used on a project. Once a letter of approval is issued, the source or producer is approved for use on projects (with the exception of steel fabricators and precast concrete plants). Approved products, sources, and producers are listed in the Materials Approved Products Listing Enterprise (MAPLE). Approval for a source or producer may be rescinded at any time if it no longer meets the requirements of the IM. The plans, developmental specifications, and special provisions may also contain lists of approved sources.


The project inspector will document information about this material such as product name, source, date, producer, and lot number in the project files.


Most approved sources also require a certification.



For some items made up of miscellaneous materials, inspection and approval will be done by the District Materials Engineer at the supplier’s warehouse.



This information must be submitted to, and reviewed by the Iowa DOT Design Office or Bridges and Structures Office, before the material can be incorporated in the project.



The project inspector must have a copy of the final inspection report prior to incorporating the item into the project. The report will vary depending on the Materials IM requirements for the item fabricated. Final acceptance is by construction personnel at the project site, and is based on the proper documentation and the condition of the component.



 (May also be referred to as “As Per Plan, Approved By RCE, or Manufacturer Recommendations”) The project inspector must document information about this material such as product name, source, producer, lot number and date produced in the project files. The inspector will make sure the material meets the requirements of the plans, the Engineer, or the manufacturer before the material is used. Visual approval requires construction personnel to visually inspect the material to determine if it complies with the specifications. Visual approval is appropriate for non-critical items such as sod stakes, where compliance can be readily determined by visual means. If there are questions on specification compliance, samples will be taken for testing.



The IAP evaluates all sampling and testing procedures, personnel, and equipment used as part of an acceptance decision (Includes Contractor, Contracting Agency, and consultant). Independent assurance includes evaluation based on:


Calibration checks

Split samples

Proficiency samples

Observation of sampling and testing performance


The test method and the frequency of test are in the Appendices. Calibration checks and proficiency samples testing is covered in IM 208.



The FHWA allows and encourages alternative acceptance methods for small quantities of non-critical materials.  Appendix X contains a list of those materials and maximum quantities for which alternative acceptance methods may be appropriate.  The Project Engineer or District Materials Engineer may still require the normal acceptance method for a material when it is considered critical in the intended application.



Appendix A     Roadway & Borrow Excavation & Embankments

Appendix B     Soil Aggregate Subbase

Appendix C     Modified Subbase

Appendix D     Granular Subbase

Appendix E     Portland Cement Concrete Pavement, Pavement Widening, Base Widening, Curb & Gutter & Paved Shoulders

Appendix F      Asphalt Mixtures

Appendix H     Structural Concrete, Reinforcement, Foundations & Substructures, Concrete Structures, Concrete Floors, & Concrete Box, Arch & Circular Culverts

Appendix I       Concrete Drilled Shaft Foundations

Appendix K     Cold-In-Place Recycled Asphalt Pavement

Appendix L      Granular Surfacing/Driveway Surfacing

Appendix M     Concrete Bridge Floor Repair & Overlay & Surfacing

Appendix P     Surface Treatment (Seal Coat, Microsurfacing, Slurry, Joint Repair, Crack Filling & Fog Seal)

Appendix T      Base Repair, Pavement Repair

Appendix U     Granular Shoulders

Appendix V     Subdrains

Appendix W    Water Pollution Control, Erosion Control

Appendix X     Acceptance of Small Quantities of Materials

Appendix Z      Supplemental Guide, Basis of Acceptance