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Roadside Management Toolbox

Vegetation Control (minor Concrete)

Shotcrete Standard Plan

What is This Treatment?

This is a new standard treatment to control weed growth under guard railing and should be used on all applicable projects. Vegetation Control (Minor Concrete) consists of minor concrete (that may include crumb rubber and polypropylene fibers) applied beneath sign posts, guardrails, and adjacent to median barriers.

To accommodate rotation of guardrail and median barrier posts during vehicle impact, the area immediately adjacent to posts must include a "leave-out section" that is filled with a weaker mortar mix.

* Attachment: Memorandum Vegetation Control- Concrete Pavement Under Guardrail/Thrie Beam Barrier

When and Where to Use This Vegetation Control?

Use this treatment on all new installations of guardrail or thrie beam barrier where repetitive maintenance activity to control vegetation would be otherwise be required. This treatment may also be used to provide vegetation control beyond the gore area, in narrow strips, on side slopes and below roadside sign posts. This product may also be colored and/or stamped with a pattern for additional texture.

Guidance for this treatment is included in the Highway Design Manual in Index 706.1, Roadside Management, and in the Project Development Procedures Manual in Chapter 29 and Appendix L. The guidance in these manuals states that vegetation control under guardrail is required in the following situations:

  • Metal beam guardrail, including standard railing, terminal system end treatments, guard railing at structure approach and departures, and at fixed objects should included vegetation control. For more detailed information regarding placement of vegetation control consult with both the District Landscape Architect and District Maintenance. See the Standard Plans for minor concrete vegetation control.
  • Thrie beam barrier, including single thrie beam barrier, double thrie beam barrier, at structure approach and at fixed objects should include vegetation control. For more detailed information regarding placement of vegetation control consult with both the District Landscape Architect and District Maintenance. See the Standard Plans for minor concrete vegetation control

Map:

Map of Existing Guardrail and Chemical Vegetation Control

 

Benefits:

  • Correctly designed and installed, the life cycle cost of this material should be similar to concrete paving.
  • Wide variety of colors available for the designer to specify to match soil color.
  • Easily installed by contractors and maintenance crews with standard tools and equipment.

Limitations:

  • Due to rigid nature of this treatment, a "leave-out section" must be formed at each guardrail or median barrier post and filled with a grout mix. See Standard Specifications and Details below.
  • According to FHWA Report No. FHWA/TX-04/0-4162-2, Dynamic Response of Guardrail Systems Encased in Pavement Mow Strips, concrete paving areas under guard railing which include grout-filled leave-outs at posts are considered to have a high probability of passing NCHRP Report 350.
  • This treatment is not recommended for existing guardrail as it may be cost prohibitive due to grading and excavation required to install the treatment. Other treatments (such as Weed Control Mat (Fiber)) are better suited for use under existing guard rail.

Specifications

Details:

New Standard Plans (NSPs) and Revised Standard Plans (RSPs) for Vegetation Control (Minor Concrete) are available on the web pages linked below. Look under Metal Beam Guard Railing - Typical Vegetation Control for the New Standard Plans that cover this work.

Estimated Costs:

  • $60 - 100/ yd 2
  • BEES Item - 832070

Updated: May 24, 2012