BASF Construction Chemicals Italia S.p.A., Treviso, Italy / Nordimpianti S.R.L., Chieti, Italy

Specific Chemical Admixtures for the Production of Hollow-Core Slabs

In the production of prestressed hollow-core slabs, along with the nature of the raw materials and the composition of the concrete, the machinery, be it an extruder or a slipformer, also plays a fundamental role. The difficulty of simulating in the laboratory the way the concrete is compacted by these machines, and therefore the lack of specific methods to develop and evaluate chemical products, help explain the limited use of high-performance chemical admixtures among hollow-core slabs manufacturers. This work highlights how the close collaboration between machine builders and admixture manufacturers helps develop specific chemicals for this application. These products, tested in the laboratory using the methods presented, then introduced into the plant, lead to improvements both in production efficiency and in the performance characteristics – not just the mechanical ones - of the concrete slabs.