Name: LUCIANA PAULA TESSARO MORELO
Publication date: 23/03/2023
Examining board:
Name |
Role |
|---|---|
| GEILMA LIMA VIEIRA | Presidente |
| GEORGIA SERAFIM ARAUJO | Examinador Externo |
| RUDIELE APARECIDA SCHANKOSKI | Examinador Interno |
Summary: Alternatives have been studied in order to minimize the major environmental impacts
arising from the production of cement and steel. Even adopting composite cements,
with the incorporation of alternative materials, reducing the need for cement in the
mixtures. Therefore, this work studied the viability of incorporating steel residues in the
mechanical performance of mortar durability, evaluating the partial and total
replacement of Portland Cement (PC) by granulated blast furnace slag (EGAF) and
residue from the Desulfurization process of flue gases (FGD). This research evaluated
the mechanical and durability performances of mortars produced replacing cement
with EGAF (0%, 60% and 70%) and FGD (0%, 10%, 25% and 30%), using a
water/binder ratio of 0.60. In the fresh state, consistency index, mass density,
incorporated air content, water retention and setting times were determined. In the
hardened state, the Compressive Strength, Tensile Strength by Diametral
Compression, Water Absorption by capillarity, Content of total chlorides and soluble
sulfates, in addition to the microstructure of the mortars and the leaching of
contaminants, were evaluated. ANOVA of the results obtained was performed. The
studied mixes showed a higher mass density and, consequently, a lower amount of air
incorporated in the mixtures. The results found show that the association of these
residues in place of cement improved the mechanical performance of the mortars.With
regard to compressive and tensile strength, the mortars E60F10 and E70F10 obtained
the best performances, with increases greater than 40%. The mix with 0% cement,
E70F30, obtained superior resistances to the reference mix at 28 days. As for the
dynamic modulus of elasticity, all mixes containing substitution obtained values lower
than the reference, with the exception of the E60F10 mix, which obtained a modulus
of 32 GPa. The E00F30 mix showed a reduction of more than 16% in the modulus,
which points to a mix with greater capacity to absorb deformations. As for water
absorption by capillarity, all the traits had lower water absorption than the reference
trait, with the exception of the E00F30 trait. The EGAF-containing mixes significantly
increased the performance against this property, since the mixes had 80% lower rates
of water absorption than the reference. In addition, all samples showed excellent
performance against the tests of total chlorides and sulfates. The contaminant leaching
test did not show any contaminants in harmful amounts. The results show that the
simultaneous use of FGD and EGAF to replace Portland cement is extremely
satisfactory, obtaining mechanical and durability performances superior to the
reference ones, enabling the use of these residues for the production of mortars with
low cement content.
