From Engineering Policy Guide
This guidance establishes procedures for the inspection, testing, acceptance, and reporting of geotextile for subsurface drainage, sediment control, erosion control, or as a permeable separator.
|Erosion Control Blankets TxDOT Approved List|
|Geotextile MoDOT Pre-Qualified List|
|Current General Services Specifications (MGS) By Subject|
No apparatus is necessary for field evaluation.
Geotextiles shall meet the physical and chemical requirements of AASHTO M 288 for the specified application except as modified by Secs 1011.3.1, 1011.3.2, 1011.3.3, 1011.3.4, and 1011.3.5. Erosion Control Blankets shall meet standards cited in the Texas DOT Erosion Control Report “TXDOT / TTI Hydraulics and Erosion Control Laboratory Field Performance Testing of Selected Erosion Control Products Final Performance Analysis Through the Most Recent Evaluation Cycle” and the requirements listed in the specification.
Review the condition of the material for damage during shipment or due to poor storage and handling practices. Look for damage caused by exposure to UV light, as well as any tears or holes in the material. The contractor shall furnish a manufacturer’s certification in accordance with Sec 1011.4. Review of the certification should include checking the permeability, apparent opening size, and geotextile class. The geotextile may be sampled and tested by the inspector at their discretion, if it appears that it will not meet the specification, or by request from headquarters materials. Samples should be taken as follows:
- a.) A sample for testing the grab strength should be the full width of the roll by at least 1 m. The sample shall exclude material from the outer and inner wrap.
- b.) A sample for testing the apparent opening size should be the full width of the roll by at least 1 m. The sample shall exclude material from the outer and inner wrap.
Two separate samples are necessary to run both tests.
1011.3.1.1 Basis of Acceptance
Material that appears to be specification compliant may be accepted on certification. If a sample shall be obtained, the Laboratory will determine the acceptability of the material.
A SiteManager record will be created by the inspector accepting the geotextile by certification, or by obtaining a sample. Test results on samples of geotextile shall be reported and distributed by the Laboratory in accordance with Laboratory Testing for Sec 1011.
1011.3.2 Erosion Control Blanket
The performance of the material should be confirmed after placement to establish that desirable erosion control is achieved. Construction and Materials - Central Office should be notified when poor performance is observed.
1011.3.2.1 Basis of Acceptance
Material will be accepted on the basis of the Construction and Materials qualified list. Material will be placed on the list once approved by TXDOT / TTI. When the TXDOT / TTI approval process is delayed by TXDOT / TTI, the manufacturer may submit a detailed certification indicating compliance with the specification and evidence that the TXDOT / TTI approval process has been initiated, and that MoDOT will be copied with the results by TXDOT / TTI. This, and acceptable performance in the field, will constitute approval until the TXDOT / TTI approval process has been completed.
A SiteManager record will be created by the inspector accepting the erosion control blanket on the basis of the qualified list.
1011.4 Laboratory Testing for Sec 1011
Geotextile shall be tested for Grab Strength according to ASTM D4632, and for Apparent Opening Size according to ASTM D4751.
1011.4.2 Sample Record
The sample record shall be completed in SiteManager, as described in Automation Section, and shall indicate compliance or non-compliance with the above tests. Appropriate remarks, as described in EPG 106.20 Reporting, are to be included in the remarks to clarify conditions of acceptance or rejection. Test results shall be reported on the appropriate templates under the Tests tab.