Options for finishing cast stone products

Homeowners increasingly focus on a sophisticated look of their floor and wall coverings both in interiors and in outdoor spaces. Many of them favor concrete products for this purpose, including a variety of slabs. Compared to quarry stone or tile products, concrete products come at a relatively low cost, are easy to install, and are suit-able for everyday use in both private and public spaces thanks to their dimensional stability and robustness.
Producers of upmarket concrete slabs and blocks increasingly provide their customers with top-class, premium-quality products that emphasize the sophisti-cated design of the property thanks to their visual appeal and texture in combination with a wide variety of laying patterns. SR Schindler based in Regensburg, Ger-many, supplies a wide range of individual machines and production lines for manufacturing premium-quality products that stand out visibly and tangibly from high-volume, mass-produced items thanks to their custom concrete recipes and top-class surface quality. Using such equipment and machinery enables precast com-panies to offer products for any design preference and area of application, thus expanding their business to new market segments.

When producing finished precast slabs and blocks, we can generally distinguish between wet-side and dry-side surface finishing methods.

Wet-side surface finishing
On the wet side of the production line, products are treated immediately after the end of the manufacturing process, which means that they have not hardened yet. Methods in this category include washing as well as coloring and marbleizing, especially for slabs produced on hermetic presses.
Using various formliners or tamper heads during the production process is another appropriate option for turning a smooth-surface item into a textured slab or block, for instance in an authentic slate or wooden look (Figs. 2 and 3). Formliners are custom-made plates composed of steel and rubber inserted into the forms of hermetic presses in order to function as the negative profile of the envisaged surface texture (Fig. 4).
SR Schindler has been manufacturing these liners for many years at its own production facility. The com-pany’s portfolio currently includes over 1,500 designs of up to 1,200 mm × 1,200 mm in size.

Dry-side surface finishing
The dry side of the production line provides many more finishing options. This is where cured products are treated mechanically and/or chemically in order to create their final appearance.

Blocks and slabs are most commonly finished using one of the following methods:

» grinding/polishing
» blasting
» curling
» impregnation

Additional options for paving stones and masonry blocks include:

» bush hammering/ageing
» splitting
» edge treatment