An absolute precondition for bonded construction systems is a superstructure executed in accordance with the regulations. All construction methods as permissible per RStO 01 with bonded water-permeable base course, are applicable. For traffic areas, used with motor vehicles, at least execution according to RStO 01 construction classification III is recommended.
For bonded base course we recommend to apply STEIN TEC® Drain Concrete DBT 08, which is optimally adapted to the STEIN TEC® mortar system.
A force-fit and durable adhesive bond between surface elements and bedding is very important for the technically correct execution of the bonded construction method. A high adhesive bond is decisive for load capacity and durability of bonded element surfaces. It ensures, that tensions as a result of loads and thermal stress can be transferred evenly to the subsurface which enables to largely avoid crack formation.
The adhesive tensile strength of the bedding mortar, determined on the basis of lab-body blocks, should be 1,5 N/mm² at least, according to the working paper FGSV-Arbeitspapier Nr. 618/2 “Flächenbefestigungen mit Pflasterdecken und Plattenbelägen in gebundener Ausführung” (“Surface pavements with pavings and slabs in bonded construction”).
Mortar beddings without adhesive bond to the surface element are damaging. The working paper FGSV-Arbeitspapier Nr. 618/2 requires an adhesive tensile strength of at least 0,8 N/mm² between surface and bedding for the completed construction. To achieve this, STEIN TEC® Bond Adhesive “Haftfix” should be applied in addition, if necessary.
According to the working paper FGSV-Arbeitspapier Nr. 618/2 “Flächenbefestigungen mit Pflasterdecken und Plattenbelägen in gebundener Ausführung” (“Surface pavements with pavings and slabs in bonded construction”), expansion joints at a distance of 4 to 6 m in longitudinal direction shall be executed in bonded pavements and slabs.
These expansion joints enable to reduce cracks, but not to completely eliminate them.
The element construction method is an inhomogeneous construction method as a result of its processing in sections and the influence of diverse conditions during the construction phase. Stresses, due to thermal stress and loads, can relieve themselves by forming a crack in unforeseeable areas – comparable with the weakest link in a chain.
Expansion joints are constructionally complex and require regular maintenance. Applying our products, under appropriate conditions thermal expansions of element surfaces can be absorbed almost without macroscopic crack formation as result of the high adhesive bond between surface and bedding and the E-modules optimally adjusted with one another. For consideration of details, please contact our technology department.
If expansion joints or notches are predefined in the base or the surface course, these must be adopted to the element surface.
Furthermore, expansion joints shall be executed at connections to buildings and fixtures, e.g. manhole covers, street gullies, as well as at areas with changes in rigidity. The construction type of the expansion joints depends on the expected traffic loads. The protection of non-pressure resistant installations and the construction of expansion joints, please coordinate with our technology department.
Near-surface hairline cracks due to shrinkage are unavoidable at bonded element construction and do not constitute a defect. They can be largely avoided by specific after-treatment after jointing, see also Technical Bulletins STEIN TEC® Jointing Mortar.
As a result of cleaning, depending on the unevenness of the surface of the paving elements, a slightly lower joint-filling (2 -4 mm) compared to the paving-block or the slab surface will occur. Such joints are considered to be completely filled. At the use of paving blocks or slabs with chamfered or rounded edgings, it has to be paid attention that the jointing space is filled up only to the bottom edge of the chamfer/rounding.