How do you choose which is the best roller or paver for the job in hand? A new software program could help.
Software which can accurately predict the performance of rollers and pavers could be an important new tool for highway engineers, as long as they are using equipment manufactured by Svedala Dynapac. The company's new computer programs - CompBase for soils and PaveComp for asphalts - have been designed to help make the best use of SD equipment.
CompBase was the first software program produced by SD's International High Comp Centre at Karlskona in southern Sweden as a professional predication tool to optimise roller selection and achieve the specified compaction and density for base course and sub-base soils, including silts, sands, clays, gravels and rockfill.
Its extensive database can select the type of material to be compacted and specify a contract's required Proctor or modified Proctor maximum dry density at the optimum moisture content.
The type and model of roller or vibrating plate is keyed in, along with the volume of material to be compacted, the specified density and the time and weekly working hours available. CompBase will then calculate the machine's compaction capacity in m3/h, the area covered in m2/h and the time and number of units needed, as well as the number of passes required and the thickness of the layers.
Contractors can also use the program to check the suitability of their existing SD equipment and get the best out of it.
Svedala Dynapac's PaveComp software performs a similar task for asphalts, but is more sophisticated and complex, catering for a much greater number of variable and changeable parameters.
As its name suggests, PaveComp is really two separate but compatible interactive sub-programs: one part deals with paving and the other compaction. The software provides contractors with the most economical choice of pavers, screeds and rollers and their best combinations for different asphalt mixes, production rates and ambient and mix temperatures.
Both the Pave and Comp programs can be used independently, but data can be copied from one to the other to build up the ideal team of pavers, screeds and rollers for the job.
To find a suitable paver and screed the relevant parameters are keyed in to the Pave part of the program. These include type of mixture and foundation, laying capacity, thicknesses of the paving and compacted layer, paving width and density.
The program processes the data and provides a list of suitable types and models of paving screeds. The most suitable machines are highlighted in green; yellow indicates that a unit is borderline and red means it is unsuitable.
A selection of wheeled and tracked tractor units are also displayed to match the selected screed. The program instantly computes the minimum and maximum paving speed. Different screeds and tractor units can be changed to compare and determine the most appropriate matching combination.
Selecting matching compaction equipment is said to be just as simple. Parameters common to both paving and compaction are copied from the Pave program into the Comp section. This data is then supplemented with additional information such as bitumen penetration, binder modification, particle size, wind speed, air and base temperatures and maximum and minimum compaction temperatures.
When the machine type and model are selected from an approved list, the software instantly and automatically displays the required number of rollers, passes, frequency and amplitude settings, laying length, overlaps, rolling speed and cooling time, which is also the time allowed for compaction.