Soils & Aggregate Inspector

The Soils and Aggregate Inspector Certification Course is designed for those individuals responsible for the sampling and testing of soils and aggregates used in base, subbase and roadway embankment construction. Suggested participants would include contractor and supplier quality control personnel, consultants, testing firms and agency inspectors responsible for the quality and placement of select aggregate and soil materials.

 Certification Process

  1. Meet the prerequisites below for taking the Soils & Aggregate Inspector Certification Course.
  2. Select a course and register online and email a copy of nuclear gauge certification to
  3. Attend the Soils & Aggregate Inspector Certification Course in its entirety.
  4. Successfully pass the written and performance examinations.

Course Prerequisites

  1. High School Diploma, G.E.D. or prior approval from NETTCP
  2. It is strongly recommended that the candidate have at least six (6) months experience working on projects and in the laboratory covering the topics that the candidate will be examined on at the course.
  3. The registration form must be signed by a NETTCP certified Soils & Aggregate Inspector or the candidate’s supervisor that indicates they are aware of the experience recommendations.

Course Outline

AASHTO Process Recommended
T 2 Sampling of Aggregates YES W
ASTM D 3665 Random Sampling NO W
T 248 Reducing Field Sample of Aggregates to Testing Size YES W,P
T 27 Sieve Analysis for Fine and Coarse Aggregate YES W,P****
T 11 Material Finer than 0.075mm (No. 200) Sieve in Mineral Aggregates by Washing YES W,P****
T 311 Grain Size Analysis of Granular Soil Materials NO W
T 255 Total Moisture Content of Aggregate by Drying NO W

T 99

T 180

Moisture Density Relation of Soils YES W,P****
T 191 Density of Soil In-Place by the Sand-Cone Method NO W
T 310 In-Place Density and Moisture Content of Soil and Soil-Aggregate by Nuclear Methods YES W
T 224 Correction for Coarse Particles in the Soil Compaction Test NO W
T 272 Family of Curves – One Point Method NO W
ASTM D 2448 Identification of Soils by Visual Procedure NO W
Construction and Compaction Practices YES W


Course Exam

  1. Written Examination For New Certification and Re-certification
    • Closed book examination
    • The exam is divided into four sections
      • Sampling (20 points)
      • Laboratory Testing (30 points)
      • Field Testing (30 points)
      • Construction Practices (40 points)
    • Written examination must be completed within ninety (90) minutes.
  1. Performance Examination for New Certification and Re-Certification
    • Each candidate must perform the following test procedures within the time limits shown:
      • Reducing Sample of Aggregates to Testing Size, 5 min. (AASHTO T 248) (new certifications only)
      • Sieve Analysis of Fine and Coarse Aggregates, 15 min. (AASHTO T 11, T 27)
      • Moisture Density Relation of Soils, 20 min. (AASHTO T 99)
    • An examiner will utilize a score sheet that will document the candidate’s performance on the various steps within a test procedure.
    • Performance tests for re-certification will include only Sieve Analysis of Fine and Coarse Aggregates (AASHTO T 11 and T 27) and Moisture Density Relation of Soils (AASHTO T 99).
  1. Passing Grades for New Certification and Re-certification
    • Certification or re-certification will be granted to a candidate who achieves the following:
      • Written Examination - a minimum grade of 60% must be achieved for each of the four sections in the examination with an overall minimum grade of 70% for the entire examination
      • Performance Examination - a minimum grade of 90% for each test procedure
  1. Re-examination Policies
    • A person failing the written examination but passing the performance examination will be required to retake the written examination only.  Only one (1) re-examination will be allowed.
    • A person failing one (1) performance test and passing the written examination will be required to retake that one (1) performance test only.  Only one (1) re-examination is allowed.
    • A person failing more than one (1) performance test and passing the written examination will be required to retake the entire performance examination.  Only one (1) re-examination is allowed.
    • A person failing one (1) or more of the performance tests and failing the written examination will be required to retake the entire certification course and examinations at full cost.
    • The cost of a re-examination is $100.00 and re-examinations must be completed within six (6) months of the candidate’s initial examination date.


Required course and examination for continued certification as a Soils and Aggregate Inspector. The course will include a review of important topics and instruction on changes in the industry, equipment, specifications and test procedures.
  • Cost:             Visit our Website
  • Course:         Two days classroom and laboratory
  • Class Size:    10 - 20
  • Examination: Written and Performance

Re-Certification Process

  1. NETTCP Certified Soils & Aggregate Inspectors wanting to maintain their certification are required to attend a re-certification course in its entirety and successfully pass the written and performance examinations. Select a course and register online.  A copy of your nuclear gauge certificate is not required for re-certification.
  2. Any candidate who fails the re-certification exam(s) and subsequent re-test is required to attend a new full certification course and pass the examinations.