Attachment_0002_-_Guide_Schedule_of_Sampling_&_Testing.pdf

GGUIDE SCHEDULE OF SAMPLING & TESTING

MAY 2016

UUsing the Guide Schedule

Research of sampling and testing rates listed for project tests in the following Guide Schedule show that the Department’s and the Contractor’s risk of either rejecting “good” material or accepting “bad” material range from 20% to 40%.

To reduce this risk, we recommend that the sampling rate be increased during initial production. A four-fold increase in testing frequency will generally reduce risk to approximately 5%. The intent of increasing testing at the start of production is to insure that the Contractor’s processes are in control and to establish acceptability requirements early.

There is a need to increase the frequency of testing for high-variability materials and when testing results do not meet specifications. The Engineer may require the Contractor to reimburse the Department for costs resulting from failing test results, in accordance with the specifications.

Materials incorporated in TxDOT projects are subjected to various quality assurance procedures such as testing (as outlined in this document), certification, quality monitoring, approved lists, etc. The Engineer and testing staff should familiarize themselves with materials to be used before work begins by reviewing the specifications and this document. Discuss material testing requirements with the Contractor.

Other testing required by the specifications, but not shown in the Guide Schedule, should be performed at a frequency necessary to provide adequate confidence that materials meet specifications.

NOTE: For projects subject to FHWA construction oversight activities, use the “Letter of Certification of Materials Used" to document reasons for material acceptance when a test fails. For all other projects, document the justification and explanation for acceptance of materials that fail project tests in the project file.

Assuring the quality of the product and proper incorporation of materials into the project begins with proper sampling practices. Sampling, testing, and construction inspection must be performed collaboratively to assure the specific attributes of the finished product reflect quality workmanship. Sampling guidance for hot-mixed asphalt is contained in Tex-225-F, “Random Selection of Bituminous Mixture Samples,” and the respective specification for that material. All remaining materials are covered by method and materials specifications, to which the following applies.

For acceptance testing, especially that which directly determines payment for the Contractor, sampling personnel should provide randomness in sampling by avoiding patterned sampling routines. Examples of such sampling practices are as follows:

Soils/flexible base: Vary sampling between stockpiling operations, completed stockpile, windrow, and project site. Vary the time of day sampling is performed.

Aggregates: Sample aggregates nearest the point of incorporation into the work. Vary sampling between stockpiling operations, completed stockpile, belt sampling, and if deemed necessary, railroad cars/trucks. Vary the time of day sampling is performed.

Concrete (structural and miscellaneous: Always sample as near as practicable to the point of placement. For strength testing, vary the time of day or the number of truck from which the concrete is sampled. Tests for slump, air, and temperature should be done often to ensure the consistent control of the concrete production (not applicable to miscellaneous concrete).

This Guide Schedule is applicable to all contracts associated with the 2014 Standard Specifications.

This is a guide for minimum sampling and testing.

Testing frequency may need to be increased for high material variability or when test results approach specification limits.

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TTABLE I –– EEMBANKMENTS, SUBGRADES, BACKFILL, AND BASE COURSES

PPROJECT TESTS

MMATERIAL OR PRODUCT TEST FOR TEST NUMBER

LOCATION OR TIME OF

SAMPLING (D)

FREQUENCY OF

SAMPLING (F)

REMARKS

RETAINING WALL

(SELECT BACKFILL)

(continued)

Soundness Tex-411-A During stockpiling operations, or from completed stockpile

1 per source, per project

Test when backfill sources appear to contain particles such as shale, caliche, or other soft, poor-durability particles.

Sample in accordance with Tex-400-A.

In-place Density ((A) Tex-115-E As designated by the

Engineer.

1 per backfill lift, per wall

Not required for rock backfill. For walls greater than 500 ft. in length, perform one test per lift for every 500 ft. in length. ((F) Correct the moisture contents measured by nuclear density gauge in Tex-115-E with the moisture contents determined in accordance with Tex-103-E for each different material or notable change in material and adjust the density accordingly.

UNTREATED BASE

COURSES

Liquid Limit

(A) Tex-104-E

During stockpiling operations, from completed stockpile, or windrow

(B)

Each 5,000 CY Sample in accordance with Tex-400-A.

Plasticity Index

(A) Tex-106-E

During stockpiling operations, from completed stockpile, or windrow

(B)

Each 5,000 CY

Gradation

(A) Tex-110-E

During stockpiling operations, from completed stockpile, or windrow

(B)

Each 5,000 CY Sample in accordance with Tex-400-A.

Moisture/Density Tex-113-E From completed stockpile at the source ((E)

Each 20,000 CY Not required for ordinary compaction.

Sample in accordance with Tex-400-A.

Wet Ball Mill

(A) Tex-116-E

From completed stockpile at the source

((E) Each 20,000 CY As required by the plans.

Sample in accordance with Tex-400-A.

Strength

(A) Tex-117-E

From completed stockpile at the source

(E) Each 20,000 CY

As required by the plans. When base material is from a source where the District has a record of satisfactory triaxial results, the frequency of testing may be reduced to one per 30,000 CY. If any one test falls below the minimum value required, the frequency of testing will return to the original frequency of 20,000 CY.

Sample in accordance with Tex-400-A.

Testing frequency may need to be increased for high material variability or when test results approach specification limits.

TTABLE I –– EEMBANKMENTS, SUBGRADES, BACKFILL, AND BASE COURSES

PPROJECT TESTS

MMATERIAL OR PRODUCT TEST FOR TEST NUMBER

LOCATION OR TIME OF

SAMPLING (D)

FREQUENCY OF

SAMPLING (F)

REMARKS

UNTREATED BASE

COURSES

In-place Density

(A) Tex-115-E As designated by the

Engineer Each 3,000 CY, min. 1 per lift

Correct the moisture contents measured by nuclear density gauge in Tex-115-E with the moisture contents determined in accordance with Tex-103-E, as necessary for control, for each different material or notable change in material and adjust the density accordingly. Materials such as RAP, gypsum, lime, cement, and iron ore tend to bias the counts for nuclear density gauges.

Thickness ((A) Tex-140-E As designated by the

Engineer Each 3,000 CY Not required where survey grade control documents compliance.

TREATED

SUBGRADE AND

BASE COURSES

SUBGRADE

BEFORE

TREATMENT

Organic Content Tex-148-E As designated by the Engineer

1 per 500 linear feet or 5,000 CY

Required for existing subgrade material and material imported from a borrow source. Soil survey and geologic maps may be used to determine sampling locations.

Sample in accordance with Tex-100-E.

Sulfate Content Tex-145-E As designated by the Engineer

1 per 500 linear feet or 5,000 CY

Required for existing subgrade material and material imported from a borrow source. Soil survey and geologic maps may be used to determine sampling locations.

Sample in accordance with Tex-100-E.

NEW BASE

MATERIAL

Liquid Limit

(A) Tex-104-E

During stockpiling operations, from completed stockpile, or windrow

(B)

Each 5,000 CY When central mix site or plant is used, windrow sampling may be waived.

Sample in accordance with Tex-400-A.

Plasticity Index

(A) Tex-106-E

During stockpiling operations, from completed stockpile, or windrow

(B)

Each 5,000 CY

Gradation

(A) Tex-110-E

During stockpiling operations, from completed stockpile, or windrow

((B)

Each 5,000 CY Sample in accordance with Tex-400-A.

Wet Ball Mill

(A) Tex-116-E

From completed stockpile at the source

((E) Each 20,000 CY

As required by the plans.

Sample in accordance with Tex-400-A.

Testing frequency may need to be increased for high material variability or when test results approach specification limits.

TTABLE II –– SSEAL COAT

PPROJECT TESTS

MMATERIAL OR PRODUCT TEST FOR TEST NUMBER

LOCATION OR TIME OF

SAMPLING (C)

FREQUENCY OF

SAMPLING (D)

REMARKS

AGGREGATE

Gradation

(A) Tex-200-F, Part I Stockpile (At source or at point of delivery) One each 1,000 CY

Rate may be reduced to one each 2,000 CY if the Engineer approves a contractor quality control plan.

Sample in accordance with Tex-221-F.

L. A. Abrasion

(A) Tex-410-A Stockpile 1 per 20,000 CY

Verify the published value of the source, as listed on the current Material Producer List for BRSQC, meets the project specifications. If not, sample and test at 1 per 20,000 CY prior to use.

Sample in accordance with Tex-221-F. (B)

Magnesium Soundness

(A) Tex-411-A Stockpile 1 per 20,000 CY

Verify the published value of the source, as listed on the current Material Producer List for BRSQC, meets the project specifications. If not, sample and test at 1 per 20,000 CY prior to use.

Sample in accordance with Tex-221-F. (B)

Surface Aggregate Classification

(A)

Tex-612-J, Tex-411-A Stockpile 1 per 20,000 CY

Verify the published value of the source, as listed on the current Material Producer List for BRSQC, meets the project specifications. If not, sample and test at 1 per 20,000 CY prior to use.

Sample in accordance with Tex-221-F. (B)

Pressure Slake

(A) Tex-431-A Stockpile 1 per 20,000 CY

Same as above. Required only for lightweight aggregate.

Sample in accordance with Tex-221-F.

Freeze Thaw

(A) Tex-432-A Stockpile 1 per 20,000 CY

Same as above. Required only for lightweight aggregate.

Sample in accordance with Tex-221-F.

Unit Weight Tex-404-A Stockpile 1 per 20,000 CY Same as above. Required only for lightweight aggregate.

Sample in accordance with Tex-221-F.

24 hr Water Absorption

(A) Tex-433-A Stockpile 1 per 20,000 CY

Same as above. Required only for lightweight aggregate.

Sample in accordance with Tex-221-F.

Coarse Aggregate Angularity Tex-460-A Stockpile 1 per 20,000 CY

Only required for crushed gravel.

Sample in accordance with Tex-221-F.

Deleterious Material ((A)

Tex-217-F, Part I Stockpile 1 per 10,000 CY

Not required for lightweight aggregate.

Sample in accordance with Tex-221-F.

Decantation ((A) Tex-406-A Stockpile 1 per 10,000 CY Sample in accordance with Tex-221-F.

Flakiness Index Tex-224-F Stockpile Frequency as directed by the Engineer

Sample in accordance with Tex-221-F.

Testing frequency may need to be increased for high material variability or when test results approach specification limits.

TTABLE II –– SSEAL COAT

PPROJECT TESTS

MMATERIAL OR PRODUCT TEST FOR TEST NUMBER

LOCATION OR TIME OF

SAMPLING (C)

FREQUENCY OF

SAMPLING (D)

REMARKS

Micro Deval Tex-461-A Stockpile 1 per project or as necessary for control

Compare result to published value listed on the current Material Producer List for BRSQC. Submit sample to CST/M&P for Soundness and L.A. Abrasion testing when results differ by more than 3% points, unless otherwise directed by the Engineer. Sample in accordance with Tex-221-F.

White Rock Count Tex-220-F Stockpile Required only for Limestone Rock Asphalt. Not required when CST/M&P provides inspection at the plant. Sample in accordance with Tex-221-F.

Naturally Impregnated Bitumen Content Tex-236-F Stockpile

Required only for Limestone Rock Asphalt. Not required when CST/M&P provides inspection at the plant. Sample in accordance with Tex-221-F.

PRECOATED AGGREGATE Asphalt Content Tex-236-F Stockpile

Frequency as directed by the

Engineer when a target value is specified

Sample in accordance with Tex-221-F.

ASPHALT Compliance with Item 300

Sampled, tested, and preapproved by

CST/M&P. Take project samples when designated by the Engineer from the distributor or transport.

1 per project, per grade, per source

Sample in accordance with Tex-500-C. Binder should arrive on the project pre-approved. If not pre-approved, sample binder before use.

TABLE II –– FFOOTNOTES

A When this project acceptance test fails but the product is accepted, document the reasons for acceptance on the Letter of Certification of Materials Used or in the SiteManager Remarks field.

B Attach the corresponding QM test report for SiteManager projects to satisfy project sampling and testing requirements.

C

For acceptance testing, especially that which directly determines payment for the Contractor, sampling personnel should provide randomness in sampling by avoiding patterned sampling routines. Examples of such sampling practices are as follows:

Aggregates: Sample aggregates nearest the point of incorporation into the work. Vary sampling between stockpiling operations, completed stockpile, belt sampling, and if deemed necessary, railroad cars/trucks. Vary the time of day sampling is performed.

D Each test performed that is based on a quantity of material is considered “or fraction thereof” for calculating number of tests.