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Roadbond logoCONSTRUINDO ESTRADAS PARA CONSTRUIR NAÇÕES

Procedures

Identification of Possible Roadbond Project
Sampling
Laboratory Equipment
Construction Equipment for Trial / Pilot
Personnel
Product Training
Pilot Testing Sequence
Testing Sequence
Conclusion

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1. Identification of Possible Roadbond Project

  • The use of Roadbond must be to provide a solution for a particular construction challenge such as the lack of local good quality construction materials, to reduce clay activity in construction materials and increase load bearing properties of available materials etc.

  • The Roadbond application process must not interfere with conventional construction operations. The very same construction equipment used in conventional construction will be required and all conventional processes need to be followed.

  • Prior to commencing with any pilot or investigation, the pavement design (required layer works using all available data: traffic count, heavy vehicle count, traffic growth etc.) using relevant pavement design models need to be undertaken by the relevant authority / client. This is to ensure that design parameters are adhered to and the use of Roadbond is investigated and marketed technically and correctly as per Tradefin procedures.

2. Sampling

  • The use of Roadbond must be technically investigated and the correct and optimum Roadbond application must be determined and verified by conducting laboratory tests. It is important to note that we are not working with a computer generated model and that duplicate or triplicate tests on the same sample can generate varied results.

  •  Each authority has a technical description/guidelines of how samples for testing are to be extracted and prepared for a series of tests. It is of utmost importance that all processes and procedures that are detailed in the technical guidelines for sampling and preparing test samples are strictly adhered to.

  • Before any Roadbond testing is undertaken, a comprehensive range of  natural samples to provide an engineering classification of the material.

  • This includes: MOD / OMC Tests, Particle Size Analysis and Atterberg Limits, CBR tests. It is recommended that these tests be conducted in triplicate on the natural material.

  • All Roadbond tests will be treated with a range of Roadbond applications. It is recommended that the natural material is tested with a minimum of 5 Roadbond applications so that a wide spectrum of Roadbond applications is considered and investigated. Therefore, enough sample needs to be extracted so that the above tests are performed on representative samples from the same batch on which the natural tests were conducted. Each authority has a technical guideline to determine how much sample is required per test; hence enough samples need to be extracted so that the following number of tests can be conducted:
    - Natural Tests:
    (MOD/OMC;
    CBR;
    Particle Size/Atterberg Limits) – All in triplicate
    - Roadbond tests:
    (CBR and or UCS if lime/cement is added) 5 different dosages – All in duplicate.

  • The Roadbond dosage range will be determined from the natural test results.

  • All representative samples are to be prepared strictly as per the relevant authority’s sampling and preparation guidelines

3. Laboratory Equipment

  • All equipment for undertaking the required tests are to be calibrated with valid certification: MOD Mechanical Compactor and moulds, Balances and Scales, Sieves, Devices for conducting Atterberg Limits, CBR/UCS moulds, CBR, curing water baths.

  • For the mixing, storage and dispensing of Roadbond the following is required: clean 2 litre or 5 litre container; pipettes and measuring cylinders with maximum 1ml calibration.

  • For the curing of Roadbond treated samples (prior to compaction in moulds), require 10 containers with lids that can store up to 10kg of samples each.

  • The above requirements are also applicable to site laboratories.

4. Construction Equipment for Trial / Pilot

  • The field application of Roadbond does not require any specialised equipment.

  • A conventional water cart or water distributor is acceptable for applying the Roadbond.

  • Also require: Grader, pad-foot of grid roller, pneumatic or smooth drum roller.

  • Also need a nuclear moisture/density gauge (Troxler or Humbolt etc).

 5. Personnel

  • Design Engineer/Technologist – Undertake the pavement and layer works design.

  • Laboratory Technician: To be trained at the laboratory to conduct Roadbond testing. To conduct and oversee the Roadbond testing process.

  • Site Materials Technician: To check and confirm moisture contents and compaction requirements. To extract samples from the treated layer works materials for verification testing and as-built data.

  • Construction Foreman: To be trained in the Roadbond field application. To direct and oversee the construction process. 

6. Product Training

Product training needs to be undertaken at various levels:

  • Marketing and Sales - Agent: What is Roadbond? How does Roadbond work? How to handle and store Roadbond? What are the protocols to be followed when planning testing and trials?

  • Laboratory Testing – Laboratory Technician: How to mix and store Roadbond? How to determine Roadbond testing dosages? How to undertake laboratory testing?

  • Site Foreman: How to determine the required amount of Roadbond per construction section. How to measure the required amount of Roadbond and to dispense and mix the Roadbond in a water cart/distributor. How to train the water cart/distributor operator on applying the Roadbond solution uniformly?

7. Pilot

Step 1: Initial Viability Investigation

Client / Relevant Authority to submit to Tradefin request for product information based on a particular construction challenge, i.e. What is the problem and how can Roadbond assist in solving the problem? Tradefin to respond accordingly.

Step 2: Design Testing Sequence

Client / Relevant Authority to submit to Tradefin: Relevant Pavement / Layer works design. Conduct Tests on the natural materials (in triplicate): MOD/CBR/Particle Size/Atterberg Limits and submit to Tradefin. Tradefin to design Roadbond testing sequence.

Step 3: Training of Relevant Personnel

(AT this stage a Tradefin Representative journeys to relevant country) See Above (Product Training) – Require 1 day to train Design Engineer / Technologist + Lab Technician + Site Technician + Site Foreman.

Step 4: Laboratory Testing

Undertake Roadbond Testing under guidance and direction of Tradefin Representative. The entire laboratory testing process for the Roadbond treated samples takes 6 days.

Step 5: Field Trial

The preparation of the trial section can be undertaken whilst the test samples are being soaked for 4 days. Site preparation includes:
Setting out the start and end points.
If in-situ materials are being treated, rip up layer to required depth and break down lumps or clods of material.
If material is imported, crush material with grid roller / pad-foot so that large aggregates are broken down.
Train water cart / distributor operator.
Undertake Field Trial / Pilot
Check for compliance with design specifications:
Check for compaction requirements (test using nuclear density gauge).
Check for material quality.
Samples to be extracted from treated layer works and tested for strength parameters.

8. Testing Sequence

Step 1: Relevant Authority to undertake natural testing and submit results to Tradefin.

Step 2: Tradefin representative to design Roadbond testing dosages.

Step 3: Undertake Roadbond testing at laboratory under supervision of Tradefin representative.

Step 4: After field application, samples to be extracted from treated layer and tested for compliance with design parameters.

9. Conclusion

After more than one and a half decades our experience in road construction has resulted in the above best practise procedures and protocols, in order to serve our clients and stakeholders in the most efficient and structured manner.