erosion control products technical ... - transportation

2020 Annual NTPEP Virtual Meeting

Erosion Control Products

Technical Committee Meeting Agenda Working Session #12b

Tuesday, June 19th, 2020 2:30PM – 4:00PM

1) 2:30PM-2:35PM: Call to Order and Introductions

2) 2:35PM-2:40PM: Review of Current Technical Committee Members

3) 2:40PM-2:50M: Brief summary of the Technical Committee

(for those states not participating in quarterly calls or who are new to NTPEP).

Purpose of AASHTO-NTPEP:

QV testing on behalf of State DOT’s, to reduce duplication of effort.

Quality Verification testing under Title 23 of the Code of Federal Regulations: PART 637 - CONSTRUCTION INSPECTION AND APPROVAL Subpart B-Quality Assurance Procedures for Construction Sec. 637.207 Sampling and testing program. (B) The quality of the material has been validated by the verification testing and sampling. The verification sampling shall be performed on samples that are taken independently of the quality control samples.

Purpose of the AASHTO-NTPEP Technical Committees:

State members and industry partners provide technical feedback and administrative guidance in the development and application of product QV testing plans.

Due to the nature of the practice, the ECP TC has historically been involved in test

development, as well as being a collaborative forum for product specification.

4) 2:50PM-2:55PM: Review of how to access data in DataMine for this specific

Technical Committee

https://data.ntpep.org/ https://data.ntpep.org/Help/

a) Action Item: Look at adding an export option to search through data by test method.

b) iEngineering could look at adding a search parameter

https://data.ntpep.org/

https://data.ntpep.org/Help/


5) 2:55M-3:15PM: D6460 Flow Calibration Update, Next Steps

Hydraulic analysis indicated significant errors may be resulting from the data collection

methods specified by D6460.

To verify flow conditions, TRI has completed installation of a control/measurement weir at DDRF and run a number of trials with the 10% flumes. Jay Sprague has a presentation discussing the work and results

Consultant Feedback (FreshWater)

Chair comments and next steps

a) Testing with flow control structure indicates D6460 discharge values need to be measured by a weir or by gate calibration. TRI is relocating and discussion on future of channel testing will continue on the next quarterly call.

6) 3:15PM-3:25PM: AASHTO COMP New Technical Subcommittee, AASHTO

Erosion Control Spec. Development

Erosion Control Products is the only NTPEP TC with no independent product specifications on

which to base the testing program. ECTC specs are developed outside of DOT input.

There is a wide variation of EC product specifications among DOT’s; independently-developed specs sanctioned by AASHTO would help level product requirements across States and reduce material costs

Standardizing product specifications will simplify the NTPEP TC operation and reduce the scope

of technical issues the TC handles.

Most urgent need is for ECB and HECP specs, since those are the products with greatest usage. TRM’s may be covered under ECB or as a separate area. SRD is a more complicated application and may need to wait until the others are complete.

AASHTO COMP is the AASHTO materials standards development body. A plan exists to devolve

Geosynthetics from TS4e to a new technical subcommittee, which would also be assigned the ECP standards as they get worked in. Scott Hidden from NCDOT can expand more in that effort https://materials.transportation.org/technical-subcommittees/

a) John Blakely from MSDOT volunteered to chair the new COMP subcommittee

https://materials.transportation.org/technical-subcommittees/


7) 3:25PM-4:00PM: Future Program Structure

Brainstorming session for what might make the program more useful and more applicable to more DOTs’ business processes:

a) HECP Cyclical Evaluations

Should the future HECP evaluation program follow the current ECB cyclical schedule, or does the cycle length need to be revisited?

b) Bench-Scale Slope & Shear Testing

How many DOT’s are using Bench-scale data? Is there value in continuing this

component of the program?

c) Cyclical Large-Scale Program

In light of b., and the fact that some DOT’s require large-scale testing to be repeated periodically, would there be value in replacing the cyclical bench-scale testing with such a program?

d) Plant Audits?

Do DOT’s see value in a plant audit program? What QC testing is currently taking place in plants that would validate an audit program?

Action Item: Submit a survey to states with these questions regarding future program structure to get an accurate count. Courtney or Jace can send this out.

8) 4:00PM-4:30PM: Chair/Liaison available for Open Discussion

ASTM D6460 Calibration Current Status/Progress Report

June 2020

Presented to NTPEP ECP/SRD Technical Committee

Presented by: James E. “Jay” Sprague Lab Director, TRI Environmetal – South Carolina

ASTM D6460 History

• ASTM D6460 – 19 - Standard Test Method for Determination of Rolled Erosion Control Product (RECP) Performance in Protecting Earthen Channels from Stormwater-Induced Erosion is the large scale performance test method utilized by the NTPEP ECP/SRD technical committee for the evaluation of an erosion control product’s ability to control soil erosion under channelized flow scenarios. This test method is most commonly used for Rolled Erosion Control Products (RECP), specifically Turf Reinforcement Matting (TRM) and Erosion Control Blankets (ECB)

ASTM D6460 History

• Specifically, this test method is used extensively by industry both as part of and separate from the NTPEP ECP/SRD technical committee to determine the following performance characteristics of an RECP:

– The permissible shear limit of the material (i.e. the hydraulic shear

force, in lbs/ft², at which the underlying soil surface is eroded to 0.5 in depth from original surface elevation)

– The permissible velocity limit of the material (i.e. the hydraulic velocity, in ft/sec, at which the underlying soil surface is eroded to 0.5 in depth from original surface elevation)

• The test method is used by the NTPEP ECP/SRD Technical

Committee to evaluate products both in un-vegetated and vegetated conditions.

ASTM D6460 Current Practice

• The ASTM D6460 standard requires measurements for both flow depth and flow velocity to calculate the hydraulic shear forces and hydraulic velocities that occur during a test flow.

• The soil and water elevation measurements are taken with a verified ruler to the nearest millimeter. The reading is taken at a fixed “cross-member” location. The difference in distance (mm) from the soil surface to the water surface is used to calculate the depth of water.

• The velocity measurements are taken using a calibrated propeller driven open channel velocity probe.

ASTM D6460 Calibration

• The use of the propeller driven flow meter is of concern to the technical committee, and an effort has been undertaken to “calibrate” the upstream channel gates using a down stream weir structure to measure the flow through each channel at different gate openings and head pressures.

• The final design and implementation of this effort was initiated in early 2020 and is currently in process.

• The following slides will help visualize the construction and execution of the weir calibration device.


Preliminary Data for: 2-ft Gate Width

2-ft Channel Width 10% Channel Slope


• Data has successfully been collected from the calibration exercise for gate openings ranging from 1” – 10”. Gate openings of 2” – 6” are represented here.

• The data suggests that for these specific head gates, a gate-specific coefficient can be determined for flow rate determination during testing.

erosion control products technical ... - transportation

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