Per: MARKSSUEL TEIXEIRA MARVILA (UFV - CRP), Marina Souza Pinto (UFV - CRP), Marília Gonçalves Marques (UFV - CRP), Leonardo Carvalho Mesquita (UFV - CRP), Afonso Rangel Garcez de Azevedo (UENF)
Abstract:
The use of agro-industrial waste, such as coffee husks, in cementitious materials is a viable way to achieve the sustainable development of new construction materials. Traditionally, these residues are applied after calcination, releasing energy and financial resources. In this sense, the objective of this research is to evaluate the possibility of using coffee husks using chemical treatments with sodium and potassium hydroxide without the need for calcination. The methodology of this article consists of producing test specimens of mortar for covering and laying walls in the composition 1:1:6:1.55 (cement: hydrated lime: sand: water), using coffee husks to be incorporated in levels of 2. 5% in relation to the mass of the cement in its natural state and after treatment in sodium and potassium hydroxide. The parameters evaluated were: mass density in the hardened state, water absorption by immersion and compressive strength. XRD and SEM tests were carried out to compare the proposed treatments. The results obtained indicate that the use of treatments with NaOH and KOH allow the use of coffee husks in mortars, as the parameters obtained were compatible with this type of application. The use of natural coffee husks is not possible due to low compressive strength and high water absorption, driven by porosity. The use of alkaline treatments, especially with KOH, does not interfere with the hydration of the cement, allowing values to be obtained that are statistically equivalent to the reference composition and greater than 2.00 MPa. It is concluded that for the application of coffee husks in coating mortars and laying blocks, chemical treatment with KOH meets the necessary parameters, contributing from an economic point of view and promoting the use of an agro-industrial residue in construction materials
