Concrete is the most used construction material but it has a weak tensile strength. That is why concrete needs reinforcement iron. The purpose of post-tensioning is to increase the load-carrying capacity of concrete, for example in a cupola structure. The aim of this Bachelor's thesis was to examine the installation and use of an unbonded anchored tendon or grease tendon. The target worksite was the Matinkylä Metrocenter in Espoo. The thesis focused especially on the section G in the parking garage. The construction company Sierak Oy acted as a cooperation partner. Sierak Oy works as a subcontractor of NCC in the Matinkylä Metrocenter.

The objective was to create a detailed and logical description of the work phases of a post-tensioned in-situ cast concrete slab. The thesis has a theoretical and practical section. The purpose of the theory is to support the description of work phases and introduce the main terms of the subject. In addition, the writer's experience gained during work placement on the construction site was utilized. The description of the work phases is demonstrated with photos taken in the summer 2014.

As a result of the thesis a clear and logical description of the work phases was obtained. The description includes the main work phases of a posttensioned in-situ cast concrete slab.