2006 TPD0611011 Soiltac Trial Specifications

Khumane Mine
0001-01-01
Khumane Mine

1001: INTRODUCTION AND SCOPE
The development of the new Assmang iron ore mine at Sishen involves among others the construction
of over 1mil square meters of gravel haul roads and gravel surfaced platforms. During the cause of the
field surveys to identify possible sources of construction materials, it became clear that particularly
wearing course material available on site is highly variable and do not always conform to the required
specification for maximum aggregate size, bearing capacity and Plasticity Index.
Soil additives have been used to improve the properties of natural materials for some time with
variable success. Soiltac is a liquid copolymer emulsion marketed by Soil & Dust Solutions as a
stabilization and dust suppressing agent. Although the product has been used with success in other
countries, no evidence exists of its effectiveness in Southern Africa and particularly to the South
African situation. Accordingly DRA decided to evaluate the products ability to improve the available
wearing course materials properties through a series of trial sections, before implementing the product
on a large scale.
This document details the construction of the sections and describes the evaluation method that will
be used to assess the performance of Soiltac. The constructed trial sections will be evaluated with the
use of the Model Mobile Load Simulator (MMLS) and exposed to construction traffic for a period of 30
days and then evaluated through a series of visual and mechanical assessments.
The MMLS is a wheel tracking apparatus that applies a pneumatic wheel load of 2.7kN at a tyre
pressure of 690kPa and a loading rate of 7,200 cycles per hour. The device will allow a comparison
between lean gravel wearing course and material treated with Soiltac after 100,000 wheel loadings.
Throughout this document the following definitions remain:
o Client: DRA
o Contractor: CONCOR
o Consultant: AFRICON
o Supplier: SOILTAC

continue reading...

1002: LAYOUT AND CONSTRUCTION OF THE SECTIONS
Three trial sections shall be constructed as indicated in Figure 1002/1. The exact position for
construction of the sections will be defined by the Client. The sections shall be underlaid by a
minimum of 500mm dumprock layer consisting of rock with nominal size greater than 50mm and less
than 5% fines. The wearing course for the 3 trial sections shall be of material obtained from borrowpit
S3 (max aggregate size 75mm) and will be constructed to a thickness of 200mm as follows:
o Section A: Control section constructed from lean S3 material compacted to 98% mod
AASHTO density.
o Section B: Soiltac section constructed to the Suppliers method specification, with the amount
of additive added and level of compaction as set by the Supplier.
o Section C: Soiltac section constructed to the Suppliers method specification, with the amount
of additive added and level of compaction as set by the Client and Consultant.
1003: MMLS TESTING
MMLS testing will be conducted as specified in the test protocol for field rut testing DD-MMLS-PD-01
(2004) attached as Appendix A. During testing no temperature adjustment, additional water or lateral
wander will be added.

Chart Graph Placeholder

1004: FUNCTIONAL PERFORMANCE ASSESSMENTS
The monitoring of the functional performance of the wearing course shall occur through the
assessment of functional performance parameters immediately after construction completion, and
then after 100,000 MMLS wheel loadings and 30 days of full scale construction traffic loading. The
functional performance parameters to be assessed are listed in Tables 1004/1 for both visually as well
as instrumentally assessed parameters.

Table 1004/1: Functional Performance Parameters for Surfacing

Chart Graph Placeholder

The Client shall be responsible for all the costs associated with; construction of the sections excluding
the cost of the Soiltac additive where the amount of additive is specified by the Supplier; providing the
necessary equipment, transport and accommodation of traffic measures required to carry out both the
visual and instrument assessments safely. The Client will also bore the costs for processing and
presenting the visual as well as instrument-assessed results. Should the performance assessment
indicate that no significant increase in performance as defined below has been achieved with the use
of the Soiltac, all costs associated with the supply of the product to site will be bore by the Suppliers.
1005: VISUALLY ASSESSED PARAMETERS
(a) Definition
The detailed description and definition for the visually assessed parameters shall be as specified in
TMH12 (2000): "Pavement Management Systems: Standard Visual Assessment Manual for Unsealed
Roads", developed by the CSIR.
(b) Assessment Methodology
The visual assessment of the wearing course shall be undertaken by means of a Visual Assessment
Panel comprising the following representatives:
o Client 2 representatives
o Supplier 2 representatives
o Consultant 2 representatives
All site investigations or inspections shall be undertaken by the panel of representatives. The
arrangements and responsibilities for such inspections shall vest with the Consultant while the Client
will bore the costs. However, the Supplier shall be responsible for his own travel, accommodation and
personnel costs during the panel inspections.
(c) Assessment Specification
The visual assessment panel will quantify each occurrence of the visually assessed parameters by
rating the degree of distress according to the TMH 12 definitions and the extent as the linear length (in
metres) affected in the direction of travel. The minimum linear length to be recorded for any single
occurrence of any of the visually assessed parameters shall be 0,5 metres. Visual assessments must
be done in accordance with the specification presented in Table 1005/1.

Table 1005/1: Specification for Visual Assessment

Chart Graph Placeholder

(d) Data processing and reports
For each of the visually assessed parameters the Combined Index Value will be calculated for the
entire trial section. The Combined Index Value (CIV) for each visually assessed parameter will be
processed as follows:

Formula Placeholder


Table 1005/2: Specification for Output of Visual Assessment

Chart Graph Placeholder

Acceptance Criteria
The visually assessed parameters as well as the calculated Combined Index Value shall meet the
Acceptance Criteria listed in Tables 1005/3 for the after trafficking survey.

Table 1005/3: Acceptance Criteria for Visually Assessed DistressChart Graph Placeholder

Notes:
1 .. ./ Calculated as follows:

Formula Placeholder

Where,

 

x; = Parameter assessed initially on control (untreated) section
x, = Parameter assessed after trafficking on control (untreated) section
y; = Parameter assessed initially on Soiltac treated section
y, = Parameter assessed after trafficking on Soiltrac treated section
2 .. ./ The degree of a visually assessed parameter as specified in TMH 9 (1992)
"Pavement Management System: Standard Visual Assessment Manual for
Flexible Pavements", issued by the Committee of Land Transport Authorities
(COL TO).
3 .. ./ Combined Index Value (CIV) per trial section.

1006: INSTRUMENT ASSESSED PARAMETERS
(a) Surface ravelling (aggregate loss)
(i) Definition
Surface ravelling or aggregate loss is measured as the amount of gravel removed from the layer by
vehicular traffic. It is calculated by subtracting the cross section area from level dips or profilometer
readings taken before and after trafficking.
(ii) Equipment
Four sets of steel level stakes are to be fixed in concrete at regular intervals along each trial section at
a predefined distance from the road edge. Level dips are then measured at 0.5m intervals starting at
the edge of the road with a fish line and tape measure.
(iii) Validation and operation
Level dips will be measured by the Consultant in the presence of a representative from the Client and
the Supplier.
(iv) Position and frequency of measurement
Aggregate loss measurements must be recorded in accordance with the specification presented in
Table 1006/1.
Table 1006/1: Specifications for Measurement of Surface Friction

Chart Graph Placeholder

Data processing and outputs
Aggregate loss data shall be processed so as to produce results in the format specified in
Table 1006/2.
Table 1006/2: Specification for Output of Surface Friction Results

Chart Graph Placeholder

Surface Friction
(i) Definition
Surface friction is measured as the ratio of the force to the normal load on the wheel of a SCRIM
(Sideway-Force Coefficient Routine Investigation Machine), or equivalent approved, under wet road
surface conditions. This ratio is termed the Sideway-Force Coefficient of Friction (SFC).
(ii) Equipment
The equipment used for the measurement of surface friction shall be the SCRIM, developed by the
TRL, or similar approved machine. The equipment must be certified by the manufacturer or its agents as being in good working order and the work must similarly be certified as having been carried out in

accordance with the operating instructions.
(iii) Validation and operation
Validation and operation of the surface friction measurement instrument must be carried out in
accordance with the manufacturer's and the Employer's requirements.
(iv) Position and frequency of measurement
Surface friction measurements must be recorded in accordance with the specification presented in
Table 1006/3.
Table 1006/3: Specifications for Measurement of Surface Friction

Chart Graph Placeholder

 

Data processing and outputs
Surface friction data shall be processed so as to produce results in the format specified in
Table 1006/4.
Table 1006/4: Specification for Output of Surface Friction Results

Chart Graph Placeholder

(c) Rut Depth
(i) Definition
The rut depth is defined as the maximum vertical distance (mm) in the wheel path measured between:
o the road surface and the bottom of a two metre straight edge placed transversely across a
wheel path for full scale tafficking,
o the initial road surface level and the road surface level after MMLS trafficking.
(ii) Equipment and accuracy
The rut depth is measured:
o using a 2m straight edge and a steel ruler for full scale trafficking,
o using the standard MMLS profilometer for MMLS testing.
The maximum reading will be recorded to the nearest 0.1mm.
(iii) Validation and operation
Level dips will be measured by the Consultant in the presence of a representative from the Client and
the Supplier. Profilometer readings will be taken by the qualified MMLS operators.
(iv) Measurement specification
Rut depth measurements must be taken in accordance with the specification presented in Table
1006/5.

Table 1006/5: Specification for Measurement of Rut Depth

Chart Graph Placeholder

(v) Data processing
The average maximum rut depth for 10 readings shall be reported for full scale trafficking. For MMLS
testing the average maximum for 4 readings shall be reported.
(d) Acceptance Criteria
The instrument assessed parameters shall meet the Acceptance Criteria listed in Tables 1006/6 for
the after trafficking survey.
Table 1006/6: Acceptance Criteria for Instrument Assessed Distress

Chart Graph Placeholder

Notes:
1 .. ./ Calculated as follows:

Formula Placeholder

where,
x, = Parameter assessed after trafficking on control (untreated) sectio

1007: EVALUATION OF ACCEPTANCE
The following "rules" shall be applied by the Consultant to determine the success of using the soil
additive.
Should 10% or more of the performance criteria not be met, the soil additive would be judge not
appropriate and the cost of supplying the additive used during construction of the trial section will be
bore by the Supplier.

APPENDIX - A

Complete the form below to download this document now.
Fill out the form to get access to the complete article.