The fast track
January 1st 2004 Fast track pumped industrial floor screeds by Cyril Potter, chief chemist, Ardex UK Limited
There is an increasing demand for flat, hard wearing surfaces in light industrial premise such as warehousing, electronic assembly plants, packaging, etc where the floor will be required to take pedestrian and wheeled traffic. Such floors can be installed in new construction work as well as improving concrete floors in existing buildings. The fast track pumped industrial floor screeds are available as a finished floor surface or for coating with resins and other finishes to provide a smooth floor that is easy to maintain in such locations.
The majority of these floors will usually be coated with at least a sealer or a resin to provide either a decorative appearance and for the practical advantage of providing an impervious surface that can be easily cleaned and maintained. There will also be circumstances where the fast track pumped industrial floor screed will also provide the base for other floor finishes, such as resilient floorings ceramic floor tiles, etc. if required within the same building.
To achieve real fast track performance with pumped industrial floor screeds certain requirements have to be achieved. The primary requirements are rapid setting, rapid hardening and rapid drying properties of the pumped screed mortar, these being essential to enable early access and installation of other materials.
The secondary requirement, which is sometimes wrongly considered to be a primary requirement, is rapid application properties so that large areas can be screeded within a very short period of time compared to hand applied conventional screeds. Fast application rates are necessary but the application is only truly fast track if other work can quickly follow and the completed floor brought into use without further delay. A rapid application of a normal drying screed followed by a lengthy wait until the new screed dries only saves a few days of the construction time.
The suitability for application within design constraints of the construction is a tertiary requirement and this usually relates to the applied thickness of the fast track pumped industrial floor screed. As such screeds are applied as thin bonded screeds, this has the advantage of not significantly raising the finished floor level when improving concrete floors in existing buildings. Thicker applications are sometimes necessary when bringing floors up to the appropriate requirements detailed either in BS 8204-7, or in Technical Report No. 34 Concrete industrial ground floors published by The Concrete Society.
The selection of a fast track pumped screed will require application on a dry concrete base slab to utilise the rapidity of drying and the subsequent application of resin based coatings and sealers as well as other floorings when appropriate. Where the concrete base slab is direct to ground it should be adequately protected from rising damp by a damp-proof membrane. Where the existing concrete base still contains excess water or is not protected against rising damp then a surface damp-proof membrane will be required.
The fast track pumped industrial floor screed will always be applied as a bonded screed so it is essential to carry out effective surface preparation of concrete base slab to ensure good adhesion. This is frequently most effectively achieved by the use of dust-free contained shotblasting that will not unduly roughen the concrete surface but will selectively remove any weak or friable surface residues.
Any necessary priming or even the application of a surface damp-proof membrane on the prepared concrete surface should carefully follow the recommendations of the manufacturer concerned so that the subsequently applied pumped floor screeding mortar will be well adhered.
The mixing and pumping of the floor screeding mortar will be carried out using equipment specifically designed to not only thoroughly and rapidly mix the powder with the required amount of water but to also deliver a consistent mortar. The initial procedure is to check the consistency of the mortar being delivered through the hose by carrying out a flow test, this test is repeated whilst pumping is being carried out and after pump shutdowns to ensure a consistent result.
Once installed suitable water-based epoxy coatings may be applied to rapid drying pumped industrial floor screed within hours, acting either as a first coat of a two-coat application system or as a primer coat for thicker resin-based floorings.
The application of fast track pumped industrial floor screeds will provide the following advantages: Consistent mortar delivered once set up correctly; Speed of delivery maintains fresh edge eliminating day work joints; Large areas rapidly smoothed and levelled - 360 to over 600 m2/hour; Can overcome difficulties in access, e.g. upper floors, etc; Increased cost effectiveness for areas of over 800 m2; Real Fast Track performance can be achieved with rapid drying materials.
Resin seals, coatings and other floorings can be installed 24 hours later. More articles from Ardex UK Limited: | 
