Cara Mari Prinsloo, University of Pretoria
PAPER
Loading...
Reload document 
Open in new tab SPEAKER PRESENTATION
Loading...
Abstract
The use of precoating fluids is standard practice in South Africa to improve adhesion between aggregate and hot bituminous binders and to minimise the risk of aggregate loss. Pull-out load tests provide an indication of the load required to dislodge a stone from a bituminous binder surface (bond strength).
Method MB-8: Pull-out test method for surfacing aggregate provides repeatability challenges such as raising a scale at a constant rate whilst simultaneously reading the value from the scale and monitoring the exact moment that the stone dislodges from the surface. Ambiguity is also a concern in the MB-8 method as the use of glue may influence load readings, adding an additional adhesive element.
The first objective of this study was to develop an apparatus to improve the existing pull-out test method. The second objective was to test the effectiveness of different precoating fluids available in South Africa, to improve the bond strength between different aggregate and binder types.
The paper firstly describes the newly developed apparatus and highlights the improvement in accuracy and repeatability. Secondly, the effects of different precoating fluids containing kerosene, water and/or specific chemicals are discussed. Depending on the base binder, the study indicated that similar results can be obtained when using bitumen emulsion pre-coated material to their cutback counterpart.
About the Author
Cara Prinsloo is a third-year student in B Eng Civil Engineering at the University of Pretoria. This year she undertook an internship at TOSAS which involved shadowing and assisting with laboratory work and experimental testing of a newly automated pull-out test for the adhesion abilities of different precoating materials. She is passionate about the environment and the potential of civil engineering to further sustainability.
