Deividi da Silva Pereira

Theoretical and field evaluation of interaction between ultra-thin whitetopping and existing asphalt pavement

Ultra-thin concrete overlays or ultra-thin whitetopping (UTW), are an attractive alternative to traditional practices for the rehabilitation of asphalt pavements. However, it is widely accepted that the exiting pavement should have substantial stiffness to make a UTW a rehabilitation option. This paper re-examines this hypothesis using the performance results and structural evaluation of two experimental sections in Brazil. It is shown that structural contribution of the existing pavement is important for good performance of UTW. However, it appears that the ability of the existing pavement to ensure composite action of the individual slabs in the UTW is more important than its contribution to the flexural stiffness.

PAHs emissions by 12 Brazilian bitumens: procedure and results

In the last few years, there has been a great focus on human health and improving working conditions. Within this context, it is necessary to study the impact of the highway construction on the quality of life of workers and the environment. This paper aims to study polycyclic aromatic hydrocarbons (PAHs) emission from different bitumens commercialised in Brazil (conventional, modified by polymer or rubber and natural asphalt). The bitumens were submitted to conventional (Brazilian specifications) and rheological (SUPERPAVE classification) tests. The most usual application method is as a hot mixture. When heated, the bitumen releases volatile species and solid particles carried by gases, and this mixture is called bitumen emissions. In this fume, there are organic substances (PAHs), some of which may be carcinogenic. Therefore, the fume emitted during bitumen heating is harmful to health and should be considered both from the environmental sustainability and the worker health points of view. PAH studies were done alongside with other studies where the bitumen and the emission of some PAHs were correlated, which were measured through an experimental apparatus that generates and collects the bitumen fume. The equipment used was a nominated extraction and collection device (ECD) and the tests were conducted on laboratory benches. The fumes were collected in ECD and analysed by liquid chromatography–mass spectrometry to quantify the amount of emitted PAHs. From the research, it was possible to verify if bitumens with different behaviours at paving, from the perspective of sustainability and different impacts to the environment and human health. These emissions have an impact on health and the environment, which require further understanding.

Comportamento mecânico de material fresado após processo de estabilização granulométrica e química por meio da incorporação de cimento e cinza de casca de arroz moída

This research aims to evaluate, through laboratory testing, the feasibility of using pure and stabilized reclaimed asphalt pavement (mechanical, chemical and grading) in layers of flexible pavements. The milled materials are from BR-290 and ERS-509 roadways. Grading stabilization was performed and determined the level of 70% of milled material and 30% of virgin aggregate. For testing of compressive strength were molded into test specimens of 10x20 cm with different levels of Portland cement (CP IV-32), and determine the content of 4,86% (BR-290) and 5,37% (ERS-569) from the compressive strength of 2.1 MPa at 28 days. From these results, specimens were molded for testing the axial compressive strength, indirect tensile strength and resilient modulus; in these specimens, the cement was replaced by rice husk ash (mesh #325 and #500) in ratios of 15, 30 and 50% by weight of cement content, and put into moist chamber for 7, 28 and 160 curing days. The results showed that for compressive and tensile strength, the replacement of 15% of cement by CCA was efficient, with no drop resistance compared to the reference samples. Also evident the effectiveness of CCA, showing positive results when compared to those mixes only with the real content of Portland cement used and with the environmental appeal becomes an interesting alternative for use in pavement layers.

PAHs emissions by Brazilian bitumens

In the last few years, there has been a great focus with human health and improvement in workers’ conditions. Within this context, it is necessary to study the impact caused by the highway construction in people’s life quality. This paper aims to study PAH’s (Polycyclic Aromatic Hydrocarbons) emission from different bitumens commercialized in Brazil (conventional, modified by polymer or rubber and natural asphalt). The bitumen’s were submitted to conventional tests (brazilian specifications) and rheological (SUPERPAVE classification). The most usual application method is hot mixture. When heated, the asphalt releases volatile species and solid particles carried by gases which mixture is called bitumen emissions. Ian this fume there are organic substances (PAH`s), and some of which may be carcinogenic. Therefore, the fume emitted in the bitumens heating is harmful to health and should be considered, both from the environmental sustainability and the worker`s health point of view. PAH`s studies were done alongside with other studies about bitumens where the bitumen and the emission of some PAH`s were correlated, which will be measured through an experimental apparatus that generates and collects the bitumen fume. This equipament is nominated ECD (extraction and collection device). The fumes are collected and analyzed by LC-MS/MS (liquid chromatography mass spectrometry) to quantify the amount of emitted PAH`s. From the research, it will be possible to verify if bitumens with different behaviors at paving have, from the perspective of sustainability, different impacts to the environment and human health. These emissions, although low, have an impact not well known on health and environment.