Name: DAIANA VALT NEPOMUCENO
Type: MSc dissertation
Publication date: 28/03/2019
Advisor:
Name |
Role |
|---|---|
| JAMILLA EMI SUDO LUTIF TEIXEIRA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| JAMILLA EMI SUDO LUTIF TEIXEIRA | Advisor * |
| PATRÍCIO JOSÉ MOREIRA PIRES | Co advisor * |
Summary: Techniques for improving soils located near the sites of new pavements are becoming more necessary not only due to the scarcity of natural resources with adequate technical characteristics but also due to the economy that can be obtained with the feasibility of non-noble materials. There is a tendency to seek for stabilization alternatives using by-products from other industries. Studies using steel slag as cementitious material have gained notoriety. Thus, the objective of this work is to show the field performance of pavement structures using chemically stabilized clayey soils with desulphurization slag in base and sub-base pavement layers in comparison with the ones obtained using the commonly used technique of soil modified by Portland cement. To do so, two experimental tracks were constructed, fixing the thicknesses of the constituent layers and varying the materials used in the sub-base layers, with one track (Track 01) executed with clay soil A-7-6 stabilized with 20% of co-product KR slag and the other track (Track 02) constructed with sandy soil A-2-6 improved with 3% Portland cement. Rubber asphalt mixtures was used in the surface layer of the two studied tracks. The materials used in the constructions of all layers were collected and tested in the laboratory. The two experimental field tracks were subjected to repetitive traffic loading using the Heavy Vehicle Simulator (HVS) traffic simulator. Field performance assessments included deflections using Benkelman Beam, wheel path rutting (ATR) using Metallic Trellis, microtexture and macrotexture by British Pendulum and Sandblot tests, respectively, and, finally, visual analysis of the cracking evolution area. After the field evaluations, the performance of the studied pavement structures were predicted using the National Pavement Design Method (MeDiNa). Also, it was verified the proposed layers thickness based on the models proposed in MeDiNa, considering the load to which the sections were submitted and some of the material properties obtained in the laboratory. The results showed that Track 01, which used the clay soil mix with addition of 20% KR in the sub-base and sandy soil improved with 3% Portland cement at the base, presented performance results as good as the mixture of sandy soil improved with 3% Portland cement in both sub-base and base layers. It was verified that the evolution of the performance over time predicted by MeDiNa for both Tracks 01 and 02 were very close to the ones obtained in field for ATR and fatigue. The possibility of using KR-soil solution in the sub-base application can economical
and environmental benefits to the road construction, since it is much less expensive than other commonly used solutions, such as soil modified by Portland cement.
