ACPA presents award to Gary Godbersen
Posted: Tue Jun 06, 2017 12:27 pm<P>Development of new material technologies for the concrete paving sector continues apace and the latest innovations could provide the biggest boost for this market in many years. High performance cementitious material (HPCM) is an innovative concept that has been developed and tested for road surfacing applications as part of a project in which the UK's Transport Research Laboratory (TRL) participated. The pavement consists of a layer of high performance, steel fibre-reinforced fine mortar, in which hard polish resistant aggregate particles are embedded, forming a 10mm composite layer. As a new surfacing material, considerable work was undertaken on the development of HPCM mixes to find the best combination of properties. Testing was carried out to assess the feasibility of HPCM as an ultra-thin wearing course.</P>
<P>The initial mix-design developed was improved during the project and evolved through the selection of constituents, mix-design and laboratory application processes and assessment of behaviour. This was assessed for critical properties such as: skid resistance; binder function; protection of lower pavement layers; cracking behaviour; and bond between the cementitious and the bituminous substrate. The results showed that the thickness of the fibre-reinforced mortar layer needed to be minimised to control costs. At the same time, it needed to be thick enough to allow for good penetration of the chippings in the fresh mortar.</P>
<P>Testing showed that HPCM has great strength and integrity and there is a high probability that wearing courses of the material will be practically maintenance-free during a likely service life of 30 years, even on roads with heavy traffic volumes.Production of HPCM uses existing know-how and equipment although laying the material and inserting the chippings will require some modification to existing machines. Further testing in the field is also needed to achieve the best balance between mixing/handling/placing and the performance of the hardened material. However HPCM has the potential to offer high skid resistance, comfort, durability and moderate noise emissions.</P>
<P>The initial mix-design developed was improved during the project and evolved through the selection of constituents, mix-design and laboratory application processes and assessment of behaviour. This was assessed for critical properties such as: skid resistance; binder function; protection of lower pavement layers; cracking behaviour; and bond between the cementitious and the bituminous substrate. The results showed that the thickness of the fibre-reinforced mortar layer needed to be minimised to control costs. At the same time, it needed to be thick enough to allow for good penetration of the chippings in the fresh mortar.</P>
<P>Testing showed that HPCM has great strength and integrity and there is a high probability that wearing courses of the material will be practically maintenance-free during a likely service life of 30 years, even on roads with heavy traffic volumes.Production of HPCM uses existing know-how and equipment although laying the material and inserting the chippings will require some modification to existing machines. Further testing in the field is also needed to achieve the best balance between mixing/handling/placing and the performance of the hardened material. However HPCM has the potential to offer high skid resistance, comfort, durability and moderate noise emissions.</P>