The Laúca hydroelectric power plant, located in the province of Kwanza Norte in Angola, in the final phase of construction, is one of the largest projects currently on the African continent. The main generation circuit of the project is located on the right bank of the Kwanza river, consisting of six water intakes.

The dam is of the gravity type and is being built with Roller-Compacted Concrete (RCC), with a maximum height of 132 m. The flood discharger is integrated to the dam, with control effected by three sluices segment. The Water Supply is composed of six island-type units with a total width of 162.0 m and a maximum height of 74.4 m since its foundation, being excavated in rock, downstream of the adduction channel. The forced tunnels, starting from the shafts to the generating units of the Main Central with a slope of 4%, have a section in rectangular arc with 9.00 m of width and 12,20 m of height, with average length of approximately 1,900 m. The Main Central (Powerhouse) is of the subterranean type, whose dimensions are: 20.60 m wide and 273.30 m long, and the assembly area is 80.00 m. The block width of each unit is 30.0 m. In the construction of Laúca, more than three million cubic meters of concrete were applied, among roller compacted concrete, conventional structural concretes and shotcrete. In this technical approach, the initial characterization of the concretes will be presented, emphasizing the alkali - aggregate reactivity studies for the two dominant rock lithologies that were destined to the concretes manufacturing.