Name: WALTER JACOBELIS NETO
Publication date: 26/03/2024
Examining board:
Name |
Role |
|---|---|
| EDUARDO PEREIRA | Examinador Externo |
| PATRICIO JOSE MOREIRA PIRES | Examinador Interno |
| RAFAEL DORS SAKATA | Examinador Externo |
| RONALDO PILAR | Presidente |
Summary: Ferronickel slag (FNS) is an industrial by-product, and it’s used in construction as a potential aggregate or binder. This material is subject of research aimed at improving the mechanical properties and durability of concrete and mortar. This study aimed to evaluate the effect of incorporating FNS on the fresh and hardened state performance of pastes and mortars. FNS was incorporated to ground clinker with gypsum at mass proportions of 10%, 20%, and 30%, with a fineness of 5,900 cm²/g, as well as at 20% with a fineness of 9,300 cm²/g, to simultaneously evaluate the influence of surface area. Samples containing 20% limestone filler were also produced. The pastes were evaluated in terms of fresh state properties through rheological tests and calorimetry. In self-compacting concrete mortars, technological tests including slump flow, flow time through a mini V-funnel, density, and air content were conducted in the fresh state, as well as compressive strength in hardened state mortars. Rheological tests showed a reduction in static and dynamic shear stresses of 20% and 18%, respectively, at 10 minutes, on average, for samples containing FNS with specific surface area of 5,900 cm²/g. Reductions in heat release peaks were observed in samples containing FNS, up to 22% in sample P-E30. Compositions containing FNS with specific surface area of 5,900 cm²/g showed slump flow values 16% to 29% higher than the reference at 10 minutes. This increased fluidity was maintained at 60 minutes. The sample with FNS with a specific surface area of 9,300 cm²/g showed only a 6% higher flow than the reference at 10 minutes. All samples with supplementary cementitious materials had shorter flow times through the mini V-funnel, with an average reduction at 10 minutes and 60 minutes of 38% and 44%, respectively. Mortars containing FNS exhibited a proportional reduction in compressive strength of 5% to 13%, higher when the FNS content was higher. The cement intensity index was on average 13% lower with the use of FNS.
Keywords: Workability; compressive strength; mortars; cement pastes; ferronickel slag; supplementary cementitious material.
