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COMPACT - Layer design and compaction control in road construction

Please note if you are running windows 95 or 98 you will need to first install the DCOM98 drivers before you install COMPACT

Click here to download a demo version of COMPACT

PLEASE NOTE: No technical assistance can be provided for this software

About the COMPACT program

CompactThe new CSIR COMPACT version 3.0 program is based on extensive research into the influence of basic material properties (ie grading, Atterberg limits and linear shrinkage) on the compactability of untreated and asphalt road building materials.

In this research the effects of the shape and texture of the aggregate particles as quantified by the shakedown bulk density (SBD) and the weighted fractional density (WFD) on the compactability and bearing capacity of materials were also investigated. Accurate regression models were developed for the prediction of compactability properties and bearing capacities for a range of densities and moisture content levels.

The results of this research are contained in the COMPACT software, which allows the roads engineer to use the results of this work with ease and confidence

Input Information Required

  • Atterberg limits (Casagrande method);
  • ARD+4,75, BRD+4,75 and ARD-4,75, BRD-4,75;
  • SBD and WFD;
  • Grading after compaction;
  • Linear shrinkage;
Typical data Input
Figure 1: Typical data output

If the SBD and/or WFD values are unknown, it is still possible to make reasonable predictions of the compactability properties - but not of the bearing capacity.

Outputs - Bearing capacity information

The California Bearing Ratio (CBR) is predicted at the CMC, OMC (lowest value of OMC(vib) or OMC(mod. AASHTO)) and "soaked" condition for the following density levels (see Figure 2 below):

Typical tabular output
Figure 2: Typical tabular output
Grading curve graph
Figure 3: Grading curve graph

The CBR is shown in both tabular and graphic form.

Outputs - Compactability properties for Asphalt materials

The program can also be used for asphalt mixes, i.e. coarsely graded or fine to well-graded asphalt mixes (eg Porous, SMAs, continuously graded and gap-graded mixes).

Properties that are predicted include:

  • the optimum and zero air voids binder contents;
  • BRD;
  • binder film thickness;
  • interparticle and total air voids;
  • maximum theoretical density (Rice) for both the interparticle air voids and total air voids.

The binder contents at 3% and 4% air voids are also predicted, as well as the other properties mentioned above for these binder contents.

Special Features

  • Windows version is supplied;
  • COMPACT is user friendly and easy to use;
  • The input data and output results can be viewed on the screen, printed out (input and results on the same A4 sheet) or saved as an electronic file;
  • Grading and bearing capacity graphs can be viewed on the screen, printed or saved as an electronic file;
  • COMPACT has been verified for a range of materials including crushed stone (G1, G2), natural gravels, and sandy and clayey materials (ranging from A-1 to A-7-6);
  • Predictions may be expected to be accurate to within 10%;
  • The software is able to discern whether the material has a coarse or fine to well-graded grading. Materials on the coarse side of the Talbot curve (n=0,51) are taken as coarse;
  • The compactabiity models for coarse material are different from the models for fine to well-graded materials. In the case of untreated coarsely graded materials no prediction is made about the bearing capacity (i.e. CBR) as too little information exists;
  • The program has a choice of three sieve ranges, namely the European, SA untreated and SA asphalt standard sieve ranges;
  • It can also be used with equivalent non-metric sieve ranges (US and British imperial), in which case the MDDs are expressed in lb/ft3;
  • Any of the three sieve ranges may be used to evaluate either untreated or asphalt material;
  • The graphs of the actual grading and of the adjusted grading (due to differences between the BRDs of the coarse and fine fractions of the grading) as well as that of the ideal grading (i.e. Talbot with n=0,51) are also plotted on a log-linear scale to enable the engineer to visualize the quality of the grading;
  • When the SA untreated sieve range is used for untreated material the grading envelopes for G1, G2, G3 and G4 aggregates for both 26,5 mm and 37,5 mm maximum particle sizes are plotted with the grading curve. If the untreated material does not fall in any of these classes it should just be listed as "other", in which case the grading envelopes will fall away.

L Information

In order to use the full version of the Compact Version 3 program, please send your user key to the e-mail address below. A license code will be given to you. No technical assistance can be provided by CSIR.

PO Box 395
Fax: +27 12 842-7081


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Last Modified on 14 August 2008