Properties of Modified Warm-Mix Asphalt Mixtures Containing Different Percentages of Reclaimed Asphalt Pavement

The Rapid reduction of energy resources and the escalated effects of global warming have created a strong motivation to find some new techniques in the field of paving construction. Adopting new technologies, such as warm-mix asphalt (WMA) or the recycling process of asphalt can be very helpful for the economy and have a significant impact on the environmental footprint. Thus, this research aimed to study the mechanical and durable characteristics of modified WMA mixtures using (1.0%, 1.5%, and 2.0%) Sasobit REDUX®, (0.3%, 0.4%, and 0.5%) Aspha-Min®, and (0.07%, 0.1%, and 0.125) ZycoTherm® additives corresponding to three percentages of reclaimed asphalt pavement (RAP) (20%, 40%, and 60%). Three mixing temperatures have been conducted in this study to generate WMA mixtures at (135 °C, 125 °C, and 115 °C) corresponding to three compacting temperatures (125 °C, 115 °C, and 105 °C). The mechanical properties of the developed WMA mixtures have been evaluated using the Superpave volumetric properties (air voids, voids filled with asphalt, and voids in mineral aggregate), while the durable properties have been investigated using the resilient modulus test (MR) at 25 °C, resilient modulus ratio (RMR), and Hamburg wheel-track test in terms of permanent deformation, moisture susceptibility, and rutting resistance. To make the WMA mixtures accept high quantities of RAP (>25%), an insignificant increase in the amounts of WMA additives was needed to produce mixtures carrying sustainability labels. Results indicated that all the used additives had pushed the WMA mixtures to achieve considerable mechanical properties, whereas the best properties for the WMA mixtures containing 0%, 20%, 40%, and 60% of RAP have been achieved by mixing with (1.0% Sasobit REDUX® @ 125 °C), (1.0% Sasobit REDUX® or 0.3% Aspha-Min® @ 135 °C), (1.5% Sasobit REDUX® @ 125 °C), and (2.0% Sasobit REDUX® or 0.5% Aspha-Min® @ 135 °C), respectively. On another hand, the best durable properties have been achieved by mixing the mentioned WMA mixtures containing 0%, 20%, 40%, and 60% of RAP with 0.07%, 0.07%, 0.1%, and 0.125% of ZycoTherm® at 153 °C, respectively. Using such additives in the recycled WMA mixtures made it possible to activate waste recycling in the paving industry

Fatores associados à adequação do cuidado pré-natal e à assistência ao parto em São Tomé e Príncipe, 2008-2009

Neste artigo, foram identificados fatores sociodemográficos associados com o cuidado pré-natal e com a assistência ao parto em São Tomé e Príncipe. A amostra foi composta por 1.326 nascidos vivos de mulheres de 15 a 49 anos que participaram do Inquérito Demográfico e Sanitário de São Tomé e Príncipe, 2008-2009. Foram utilizados modelos de regressão logística e multinomial multiníveis. A adequação global do cuidado pré-natal foi de 26% e da assistência ao parto de 7% quando realizado por médicos e de 76% quando realizado por enfermeiras/auxiliares. Os fatores associados ao pré-natal e à assistência ao parto adequados foram: ordem de nascimento, educação materna e o índice de bem-estar econômico. O local de residência se mostrou fator importante apenas em relação à assistência ao parto. Observou-se que os efeitos aleatórios referentes às áreas onde as mulheres residem exerceram impacto importante sobre a chance de realizar pré-natal adequado e parto com profissionais capacitados. A importância dos fatores socioeconômicos aponta para a elaboração de ações que visem reduzir a desigualdade social em São Tomé e Príncipe