SECTION 304—CONSTRUCTING DENSITY CONTROL STRIPS
304.01 Description
This work shall consist of constructing control strips in accordance with these Specifications for the purpose of determining density requirements.
304.02 Materials
Materials shall conform to the requirements for the material to be used in the course. Material used in each control strip shall be furnished from the same source and shall be of the same type as the material used in the test sections whose density requirements are established by the control strip.
304.03 Equipment
Equipment shall be approved by the Engineer prior to use. The type and weight of compaction equipment shall be such that a uniform density is obtained throughout the depth of the layer of material being com- pacted. Control strips shall be compacted using equipment of the same type and weight to be used on the remainder of the course.
304.04 Procedures
The subgrade or pavement structure course upon which a control strip is constructed shall be approved by the Engineer prior to construction of the control strip. One control strip shall be constructed at the beginning of work on each roadway and shoulder course and each lift of each course. An additional control strip shall be constructed when a change is made in 304.04 the type or source of material or whenever a significant change occurs in the composition of the material from the same source. For subbase and base aggregate materials, the maximum theoretical density from either one-point proctor test (VTM-12) or three point proctor tests (VTM-1) may be used in lieu of con- structing a control strip, at the discretion of the Engineer. The project will be divided into “control strips” and “test sections” by the Engineer for the purpose of defining areas represented by each series of tests. The size of each control strip and test section will be in accordance with VTM-10. Control strips shall be constructed using the same procedure to be used in the construction of the remain- der of the course. Rolling of the control strip shall be continued until no appreciable increase in density is obtained by additional roller coverages. Upon completion of rolling, the mean density of the control strip will be based on 10 tests taken at randomly selected sites within the control strip area using a nuclear testing device. Compaction of the remainder of the course shall be governed by the density obtained in the control strip. Each test section will be tested for required thickness. Areas that are deficient by more than the specified allowable tolerance shall be corrected in accordance with the applicable requirements of these specifi - cations. The Engineer may require an additional control strip after the completion of each 10 test sections. Each control strip shall remain in place and become a section of the completed roadway.
304.05 Tolerances
If the mean density of a test section (roadway or shoulder) does not conform to the applicable require - ments stated herein, the Contractor shall continue his compactive effort or shall rework the entire test section until the required mean density is obtained. If an individual test value does not conform to the requirements stated herein, the Contractor shall continue his compactive effort or shall rework the entire area represented by that test until the required density is obtained.
a.Roadway: The density of each test section will be evaluated based on the results of five tests performed at randomly selected sites within the test section. The mean density obtained for the five tests in each test section shall be at least 98 percent of the mean density obtained in the approved control strip. In addition, each individual test value obtained within a test section shall be at least 95 percent of the mean density obtained in the approved control strip.
b.Shoulders:
1.Aggregate shoulders: The density of each test section of select or aggregate material used in the construction of shoulders will be evaluated based on the results of five tests performed at randomly selected sites within the test section. The mean density obtained for the five tests in each test section shall be within 95 ± 2 percent of the mean density obtained in the approved control strip. In addition, each individual test value obtained in a test section shall be within 95 ± 5 percent of the mean density obtained in the approved control strip.
2.Asphalt shoulders: The density of each test section of asphalt concrete used in the construction of shoulders will be evaluated based on the results of five tests performed at randomly selected sites within the test section. The mean density obtained for the five tests in each test section 304.04
Sections that cite this one
Get an email when 304 changes
Virginia revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Road and Bridge Specifications, 2020 Edition. Pages 389–390 of 1,065. View official source ↗