Name: RODOLPHO MEDEIROS FROSSARD
Type: MSc dissertation
Publication date: 07/05/2021
Advisor:
Name |
Role |
|---|---|
| JAMILLA EMI SUDO LUTIF TEIXEIRA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| JAMILLA EMI SUDO LUTIF TEIXEIRA | Advisor * |
| PATRÍCIO JOSÉ MOREIRA PIRES | Internal Examiner * |
Summary: The most recurrent problems in asphaltic are rutting, fatigue cracking, raveling due to
the dislodgment of the aggregate materials, and potholes, and these damages are
intensified with the presence of water. In addition, a worldwide concern is the use of
natural materials from non-renewable sources, so it is necessary to search for
sustainable alternatives. An alternative aggregate material is blast furnace slag from
the steel industry. However, studies have shown that those materials have chemical,
physical and thermodynamic characteristics that affect the binder-aggregate adhesion.
Thus, it is necessary to broaden the understanding of the behavior of asphalt mixtures
containing slag aggregates. Therefore, the aim of this research is to investigate the
effects of the partial substitution of 25% of natural aggregates (AN) by air-cooled blast
furnace slag (ACBFS) in asphalt mixtures, with and without the addition of fillers of
different chemical compositions (hydrated lime, electrostatic precipitator (EP) powder,
AN powder and ACBFS powder), checking the influence of the characteristics of each
material on the fracture properties of asphalt mixtures subject to moisture damage. For
this, specimens were subjected to induced moisture-damage and static semi-circular
bending (SCB). The results indicated that mixtures with both aggregate compositions
showed similar behaviors. The addition of hydrated lime provided greater rigidity to the
mixtures and greater resistance to moisture damage. The addition of EP powder also
promoted an improvement in the resistance to moisture damage of the mixtures and
maintained the capacity of the samples to absorb energy, in addition to contributing to
the ductility gain of the asphalt mixtures after moisture conditioning. It was realized that
the steel aggregate can be a sustainable alternative and with great potential for the
partial replacement of natural aggregates in asphalt mixtures as long as additions are
incorporated to solve its deficiency in the adhesion to the asphalt binder.
KEYWORDS: Steel aggregates; Adhesiveness; Moisture-induced damage; SCB;
Fracture.
