1. Michael Kidgell, Prof Wynand JvdM Steyn, Prof Gerrit Jordaan
Effect of Nano-Modified Emulsions (NME) (Nano-Silanes) Stabilizers on the Properties of Dolomite
Michael Kidgell,
Prof Wynand JvdM Steyn,
Prof Gerrit Jordaan
8 July 2019

2. The Problem
Provision of good transport infrastructure, preservation & timely rehabilitation prerequisites to economic growth
Costs continuously increasing - consuming scarce available funds
Investigation, testing and application of “alternative” new road building products, including nano-materials essential
Effect of nano-silanes stabilising agent on properties of dolomite material evaluated

3. Methodology Main objectives determine whether stabilising agent would
make dolomite water-repellent
reduce moisture sensitivity of dolomite
improve understanding of material behaviour
22 samples
Neat & Stabilized
Grading tests & Atterberg Limits
Optimum Moisture Content
X-Ray Diffraction (XRD) & X-Ray Fluorescent (XRF)
0.075 mm & mm fractions

4. Main results XRD scans Ankerite contained
mainly Quartz (SiO2)(>20%)
Illite (2 to 3%)
Kaolinite (<2%)

5. Main results Importance of identifying presence & type of clays
Neat material
average GM of relatively good quality
G4 material
AASHTO A-1-a (gravel sand)
Stabilised material
NME1 - recommended material classification system for Nano-Modified Emulsions (Jordaan et al., 2017a) and TG2 (Asphalt Academy, 2009)

6. Atterberg Limits - Neat & Stabilised Material
Effect of nano-silanes
Deep penetration into substrates achieved due to small molecular size (<5 nm in size)
Interaction of nano-silanes with free energy surrounding molecules of natural materials, changes surface atom arrangements of aggregates
Nano-silanes react with themselves and any hydroxy (OH) groups within substrate when moisture is present, forming silicone resin network
Smaller nano-silane particles formed protective layer - reducing susceptibility of dolomite to water
Dolomite effectively water-repellent - preventing water reacting with problem minerals in dolomite & causing weathering

7. Benefits 40 000 l water saving per 1 km of 2-lane road
Water-sensitivity of Dolomite
Nano-silane treatment

8. Conclusions
Addition of nano-silanes stabiliser improved properties of dolomite
slight reduction in plasticity of soils - reducing effect of moisture variations
acted as lubricant for compaction
proposed classification system & materials criteria allows for better utilisation of naturally available materials possible & practical
Cost-effective, safe & sustainable road infrastructure