RheoFalt HP-AM is a penetration corrector that recomposes the bitumen closer to its original chemical composition. This doesn’t mean it combines hard bitumen with soft components like wax and oils, but actually improves the chemical part of the bitumen that increases by ageing and refinery changes. The result is a softening that was originally part of the existing bitumen itself. An extra effect from use of RheoFalt HP-AM is the isolation of polar agglomeration of the asphaltenes, which results in longer lifetime durations.
The most commonly used bitumen penetration grades are 40/60 and 70/100.
It is now the tendency to increase the recycling percentages. This means that it is more difficult to reach the softness of the desired penetration grade.
The need for an additive, which corrects this hardening effect, is clearly desired. This is the only way to keep asphalt performance within its proven classification, and enable designers to keep working with the characteristics they expect from these penetration grade bitumen.
The theoretical penetration is 10.000.000 and therefore very effective for improving the penetration of hard bitumen with small addition rates. Because RheoFalt HP-AM is similar to the original molecular composition it is not sensitive to overdosing. The hardest and most ageing bitumen can be restored to all desired penetration levels. RheoFalt HP-AM makes it possible to correct any bitumen to a custom desired level, within a range of 10 points penetration.
A calculation program to help you decide the required dose of RheoFalt HP-AM is available. The use of RheoFalt HP-AM already led to solutions with 100% of recycling asphalt, stabilising bitumen which were not useable in its origin.
Test Results in bitumen
Rheofalt HP-AM recovers resin component, restores colloidal equilibrium and isolates polar agglomeration of the asphaltenes. Figures are based on fresh bitumen research (50/70 and PMB25 / 55) to establish a 0-point. Aging is done with RTFOT (75 minutes, 164 C) and PAV (20 hours, 90 C and 2 MPa). Comparing research data is fresh bitumen, aged bitumen and aged bitumen with 5% and 10% Rheofalt HP-AM.
Empirical Pavement Design
Although concepts for empirical pavement design procedure were described as early as the 1950's interest in these procedures became renewed in the 1980's. Since that time, significant advancements in computer capabilities have occurred, pavement technology, analysis, and testing have evolved, and a great number of countries worldwide have either initiated or implemented empirical pavement design procedures.
Ventraco Innovation Centre developed a tool to calculate the optimum, most environmentally friendly and cost effective asphalt composition. This method is tested and verified on it accuracy on real asphalt production over many years and several 100.000 tonnes of asphalt. The Log-Pen method is accurate to ± 5 penetration points.
For designing asphalt mixes and road constructions we need certain behavioral characteristics in order to predict the desired thickness. This is related to traffic load and desired lifetime. The stiffness and resilience of the used bitumen are responsible for the behavioral characteristics in the asphalt mixes. In 1935 we introduced the penetration and penetration index of bitumen to classify and control the predictable behaviour in designing calculations. This method has worked for all these years, and has brought designing properties and behaviour in practice together. Worldwide there is no designing method that works without penetration and penetration index levels. For the past 80 years penetration and penetration index classification has brought bitumen and asphalt mixes into reliable use, and has been responsible for predictable lifetimes.