Site icon McAsphalt

Base Stabilization


Base Stabilization

The purpose of base stabilization is to increase the bearing capacity (or strength) of the roadbed materials. Adding an emulsified asphalt, and possibly other fillers, increases the road’s firmness and resistance to weather, while reducing movement or rutting in the base layer. Mix design work performed in the lab seeks to maximize the strength of the base materials and minimize the effects of moisture and freeze/thaw cycles.

Design Criteria

In order to design a mix to satisfy the objectives of the project the existing pavement must be investigated for structural adequacy, thickness, slope and cross-fall as well as the visual appearance. Based on these criteria a proper design can be developed. In most instances the design procedure developed by Wirtgen is the accepted method of design. This design procedure is well laid out in the Wirtgen Cold Recycling Technology Manual.

The following is a guide to the design procedure:

Materials – Recycling Additives

Asphalt Emulsions:

A number of different types and grades of asphalt emulsions can be used in Base Stabilization. The proper emulsion to be used is based on a number of factors; environmental conditions (temperature and humidity), time of year, and the existing road conditions. All these conditions affect the emulsion to be used. Typically the most common emulsions used are CSS-1, CMS-2 (polymer versions included) as well as proprietary products. Compatibility between the emulsion and the reclaimed material is critical to make the system work.

Expanded (Foam) Asphalt:

The asphalt cement typically used in base stabilization is PG58-28. Softer grades can be used if the specification requirements for tensile strength can be met. To create the foam 2-3% water is injected into the hot (150-170°C) asphalt.

Blended Material:

The blended material is created by the pulverization of the underlying granular materials into a homogeneous mixture. Virgin aggregate, RAP material, or crushed concrete can be added to improve overall strength. Typically the maximum particle size is 37 mm. The pulverizing machine can control the gradation of the material through speed, milling head direction as well as the added granulars.


There are different modifiers that can be used in the FDR process. Besides the asphalt emulsion or Expanded (Foam) Asphalt, virgin aggregate may be added to improve gradation, stability or cross slope. Portland cement or lime in dry or slurry form as well as Type C Fly ash can be used to improve early strength, cohesion and resistance to moisture damage.


Aggregates used to improve the gradation or give extra strength can be virgin crusher run, recycled crushed concrete or recycled asphalt pavement (RAP). The virgin aggregate can also be coarse aggregate if the gradation needs to be corrected due to the fine nature of the pulverized material.

Performance Guidelines

In order to construct a proper well designed base stabilized mix the following guidelines should be followed:

Safety Data Sheets

DescriptionPdf File
SDS – Rapid Curing Cutback

Related Resources

DescriptionPdf File
Research – The Fundamental Principles of Mechanical Stabilization
Research – Usage of Emulsion Mixes to Mitigate the Effect of Subgrade Movements
Research – Waterproofed Mechanical Stabilization: A Discussion of a Cooperative Investigation
Research – Base Stabilization, Cationic Emulsions, High Float Emulsions, Polymer-Modified Emulsions
Product Data Sheet – CSS-1
Product Data Sheet – CSS-1H
Product Data Sheet – HF-500M LD
Product Data Sheet – RC-30
Pavement Process Overview – Base Stabilization
Product Data Sheet – Colasphalt Prime
Product Data Sheet – EP-2000 A
Product Data Sheet – EP-2000 B

Exit mobile version