Investigation of high performance concrete cover production

Concrete covers protect the rebars from corrosion by keeping them in the concrete in a safe area. Today, the use of plastic spacers is generally encountered. Although the initial mold cost is high, plastic spacers are preferred due to their fast production, low unit weight and ease of availability. However, the low adherence between concrete and plastic spacers causes problems in terms of durability, so the use of concrete spacers is becoming widespread, especially in structures where durability is important. Considering that concrete mixtures with high strength and durability are designed today, it is important to solve the durability problem that spacers play a key role in impermeability. The important thing here is that the concrete mixture used in the reinforced concrete element provides excellent adherence and the use of spacers with low permeability. For this purpose, in this study, the production and performance evaluation of cement-based concrete cover elements with high strength and durability were established. In the study, cement, fly ash, and ground granulated blast furnace slag were preferred as binder materials, and a total of 7 different mixtures were cast, one of which was a reference. In the prepared mixtures, the flow diameter and density tests were carried out in the fresh state, and unit weight, water absorption, compressive strength, loading and maximum load capacity tests were carried out in the hardened state. As a result, all of the produced concrete spacer elements met the minimum requirements of the relevant standards, and it was seen that the best performance was obtained from the binary combination of fly ash and ground granulated blast furnace slag in terms of compressive strength.