In 1999, the first international standard, super flat floor slab was constructed in New Zealand – at the 31,500m2 Farmers Deka Ltd National Logistics Centre. The project was made possible in large part by Denka CSA Shrinkage Compensating Cement.
Farmers Deka’s specification required the super flat floor to support Very Narrow Aisle (VNA) high bay racking (9.6m in height), high speed forklifted man-up truck movements and three floors of automated hung garment racking and distribution system.
The objective was to build a concrete floor with the following key properties:
Conventional slabs were not able to provide the required properties, including minimal floor joints.
A range of options were considered, including prestressing, vacuum de-watering, shrinkage reducing admixtures and fibre reinforced slabs. A slab system using Denka CSA expansive cement was selected.
Denka CSA is proven to reduce or eliminate shrinkage cracks, and enables larger slabs without joints.
The use of Denka CSA allowed for maximum joint spacing, and greater freedom in the layout of concrete placements. Joints were therefore able to be positioned in areas which had minimal or no traffic (Such as under racks). The joints were also able to be designed so that only one wheel of a forklift would run over a joint at any one time. The result is greater durability and less damage from forklift traffic.
The super flat floor slab achieved an FF65 average standard, placing it in an elite group of floors worldwide. Its successful completion heralded a significant advance in the construction of super flat industrial floors in New Zealand.