Alkaline activation of slag-cement with powder of waste glasses

VIVIANA FÁTIMA RAHHAL; MÓNICA ADRIANA TREZZA

Praga

Congreso; 15 th International Congress on the Chemistry of Cement; 2019

ICCC

The incorporation of large volumes of slag into cement generates a less volume of hydration products because the amount of calcium hydroxide (CH) from the hydration of the clinker (chemical activator of the slag) is smaller. That is why the mechanical resistance (related to the degree of hydration), is lower at early ages. The alkaline-activated slag-cement has a history starting from the 1940´s and is the most used option. In order to obtain more sustainable blending cement this paper propose the use of waste glass as alkaline activated of slag.The aimed of this study is to evaluate the behavior of waste glass powder as the inner alkalineactivator of slag when both are used in blending cement mortars. The incorporation of ground glass stimulates early age hydration, which compensate dilution and provide alkalis for activation of the slag. The pozzolanity tests show that, after 7 days the slag starts to activate and consequently thecompressive strength exceeds the dilution. However, mortars with 10 and 20% glass replacementachieve a better perfomance (with less slag and equal cement content). These improvements are attributed to the combined effect generated by the incorporation of ground glass: pozzolanic activation and provide of an alkali that maintains a high enough pH which helps to the slag activation. The results for 10 and 20% slag replacement by ground glass show better mortar flowability and compressive strength.