Suelly Helena de Araújo Barroso

Neural Estimation of Localization and Classification of Soils for Use in Low-Traffic-Volume Roads

This research proposes the development of a method of localization and prediction of AASHTO soil classification that can contribute to the decision-making process in projects for low-traffic-volume roads in the metropolitan area of Fortaleza, Ceará, Brazil. Geoprocessing and artificial neural networks were used as modeling techniques, and biophysical and spatial variables were used to explain the modeled phenomenon. The characteristics investigated (pedology, geology, geomorphology, vegetation, altimetry, and position) were correlated with the AASHTO classification. The soil AASHTO classification data were taken from projects and preexisting studies and totaled 876 points. In the development of this geotechnical estimates generation model, artificial neural network topologies were calibrated, validated, and tested so as to find a model that could best fit the set of tests. The model had an accuracy rate of 92.6% for the generation of estimates of AASHTO soil classification in the Fortaleza region, on the basis of the biophysical variables studied. The tested model was used to construct neural geotechnical maps that can be used to predict the AASHTO classification of soils not yet characterized in the lab and to predict the type of subgrade of a region not yet explored. Results show that the artificial neural networks technique is promising for geotechnical studies of low-traffic-volume roads.

Metodologia de baixo custo para mapeamento geotécnico aplicado à pavimentação

This paper presents a low-cost methodology for forecasting and mapping of CBR values (California Bearing Ratio) of soils in the energies normal compression (CBR-N) and intermediate (CBR-I), which contribute to the decision-making process as to their use for paving purposes. GIS, Artificial Neural Networks (ANN) and modeling techniques as well as biophysical and spatial variables were used as explanatory of the modeled phenomenon. The researched characteristics (pedology, geology, geomorphology, vegetation, hypsometry and position) correlated with CBR values of soils in both energy compaction. CBR data were extracted from pre-existing projects and studies in the study area, in this case, the metropolitan area of Fortaleza (MAF). Thus, they were calibrated, validated and tested in many different ANN to find the two models best fit, for the generation of CBR-N estimates and CBR-I, of the soil MAF from the studied biophysical variables. The geotechnical characteristics estimated by these models enabled the development of two Neural Geotechnical Maps stratified to predict the values, CBR-N and CBR-I. The results show that ANN technique is promising to predict the mechanical properties of soils and can assist in making decisions regarding the use of these in road projects.

Kinetic Analysis of the Thermal Behavior of the Sap of the Petroleum Plant for Producing Bio-Binders

The Petroleum Plant Sap is a bio-material that could be used for producing bio-binder in order to surrogate asphalt materials. Low amounts of this sap (up to 10%) were applied to an asphalt binder, resulting in very small changes of physical and rheological properties, what would indicate the degradation of some compounds of the sap. The present paper has the main purpose of analyzing the thermal degradation of the sap of the Petroleum Plant, what could point out the safe temperature range for applying the sap on paving applications. For that, thermogravimetry was performed on three heating ratios (5 °C/min, 10 °C/min and 40 °C/min) and the kinetic analysis of the data was processed. The results indicated that the temperature applied form the binder modification and aging simulating process were higher than the maximum safe temperature for the sap, that would be around 140 °C. It was also observed that the sap contains compounds that were oxidized during the heating process. The Thermogravimetric technique showed to be important for characterizing thermal behavior of bio-materials that are candidates for the formulation of bio-binders.

The Application of Soy Biodiesel in Bituminous Priming of Soil-Aggregate Layers of Low Traffic Volume Roads in the State of Ceara, Brazil

This work investigates the potential of penetration, in terms of bituminous prime coat, of an asphalt mixture produced adding Soy Biodiesel [BIO] to the Asphalt Cement [AC] to be used in low traffic volume roads in the state of Ceara, Brazil. The main objective of this investigation was finding a less polluting alternative, by replacing kerosene, usually applied as diluent of AC in the traditional mixture CM-30. Therefore, a comparative study was made between the traditional binder [CM-30] and the proposed mixture [40% of Soy Biodiesel and 60% of AC 50/70], named as AC/BIO. Both tested binders were used in specimens made by the stabilization of a sandy soil, adding 50% and 60% of construction and demolition waste, resulting in two different soil-aggregate mixtures. The research considered some factors that influence the extent of penetration of the prime coat: moisture content of the base, type and volume of binder used and compaction energy. The characterization of the materials used in this research included tests such as the gradation of the aggregates, CBR and Resilient Modulus of the mixtures soil/aggregate, viscosity Saybolt-Furol and penetration of the binders (traditional and AC/BIO) in the samples of soil/aggregate. The results showed that the penetration potential of the AC/BIO mixture was similar to the CM-30 keeping the technical viability.

Application of Cashew Nut Shell Liquid in Bituminous Priming of Low–Volume Roads in Ceara, Brazil

Volatile organic compounds are an environmental concern in the asphalt paving industry. A main pollution source is the so-called cutbacks (asphalts with solvents) frequently applied in the priming of base layers. In Brazil, the cutback MC-30 with kerosene is frequently used. However, the use of cutbacks has been restricted in some countries in which environmental legislation is stricter. This has led to the search for alternative materials to substitute for conventional cutbacks. This paper investigates the potential use of a mixture produced from cashew nut shell liquid (CNSL) and asphalt cement (AC) as the prime coat. The purpose is to obtain a less environmentally aggressive bituminous prime coat product. To verify the performance of the prime in sandy soils, 240 specimens were produced and primed with different products: the cutback MC-30, an emulsion MS-1C, and a mixture produced in the laboratory called AC/CNSL (60% AC 50/70 and 40% CNSL). Experimental results have shown that the prime coat is a complex material affected by factors such as the type and the rate of the applied binder, preparation conditions of the base surface, and moisture content in compaction. Results indicated the potential use of the AC/CNSL in compacted sand samples. The product can satisfactorily be used as a cutback, and it attends the parameter of penetration in the base layer.