Lêda Christiane de Figueirêdo Lopes Lucena

Potential Uses of Sewage Sludge in Highway Construction

AbstractThe sewage treatment plants generate, as by-products, large amounts of sludge containing harmful elements to the environment. This paper investigates the possibility of using 10% of sewage sludge by weight in pavement base layers. The soil stabilization technique was used to improve the residue properties to satisfy the minimum requirements for road bases. The intent of this stabilization technique was to use conventional additives as cement, lime, and emulsion. The main objective was to evaluate the strength behavior of the modified soil. Sludge-soil mixtures with different additive contents (2, 4, 6, and 8%) were prepared for testing. The modified soil samples were subjected to compaction, and then tested for the following parameters: California bearing ratio, unconfined compressive strength, indirect-tensile strength, resilient modulusa, and deterioration tests. Mechanical tests were used to estimate the optimum mix design. Test results indicated that the stabilization of mixtures of soil with ...

Rheological performance of soybean in asphalt binder modification

This study investigated the incorporation of soybean oil, first in the ranking of Brazil production, in a partial substitution to two types of asphalt binder (pure and with Styrene–Butadiene–Styrene – SBS) in order to produce warm-mix asphalt (WMA). The oil was incorporated into two conditions: new and waste, and the mix was obtained with 1%, 2% and 3% of soybean oil. The samples were analysed using the tests of penetration index, softening point, rotational viscosity, performance grade (PG), and multiple stress creep and recovery (MSCR). The results show that the addition of 1% content of new and waste soybean oil improved physical and rheological characteristics of asphalt binders. The decrease in mixing and compaction temperature was obtained in 2.7°C average for 1% of waste oil with pure asphalt binder and 3.4°C average for a 1% of new oil with asphalt binder with SBS, considering only the criterion of the viscosity curve.

Asphalt binders modified with Moringa Oleifera Lam oil

The concern with sustainable development has driven efforts to the study of green technologies to minimize the environmental impacts without compromising pavement quality. In this scenery, the paving industry has started to research and apply warm asphalt mixtures, which are produced in lower temperatures than conventional mixtures and reduce the expenses in fuels. The warm mixtures can result from the addition of an oil, usually organic, to the conventional binder, decreasing the binders viscosity. Moringa oleifera Lam Seeds possess an oil content varying between 38 and 40% and have antioxidant and lubricant properties. This study aimed to evaluate the changes in properties related to consistency and the effective variation of mixing and compaction temperatures due to asphalt modification with the oil of Moringa oleifera Lam as green additive. The Moringa oleifera Lam oil was extracted by pressing of seeds. Then, 6 mixtures were made using 50/70 PAC and Moringa Oleifera Lam oil in different proportions (0.5%, 1%, 1.5%, 2%, 2.5% and 3%), as well as a reference sample (pure PAC). The binders were analysed using Brookfield Viscosity, Penetration, Softening Point and Rolling Thin Film Oven (RTFOT) Tests. The results showed that the addition of Moringa oleifera Lam oil must be made for contents in the range of 0.5% to 1%, once that to these contents there is a significant reduction in machining and compaction temperatures (≈ 5 °C) without compromising the asphalt binder performance.

COMPORTAMENTO MECÂNICO DE MISTURAS ASFÁLTICAS RECICLADAS COM USO DE COMPACTAÇÃO POR IMPACTO E POR AMASSAMENTO

O desenvolvimento sustentavel faz com que pesquisadores e orgaos de infraestrutura rodoviarios busquem alternativas que tragam beneficios, nao so no âmbito ambiental, como social e economico. A utilizacao do material resultante da fresagem de revestimento de pavimentos deteriorados, que e incorporado as novas misturas em substituicao aos agregados novos, contribui para a reciclagem do pavimento. Essa alternativa minimiza a exploracao de recursos naturais nao renovaveis, fornece uma destinacao adequada aos residuos, alem de promover economia na recuperacao e manutencao da malha rodoviaria. Este trabalho teve por objetivo estudar o comportamento mecânico de misturas asfalticas recicladas contendo material fresado em diferentes proporcoes: 5%, 10%, 15%, 20%, 25% e 30%. Para atingir o objetivo foram realizados ensaios de resistencia a tracao e modulo de resiliencia, compactados por impacto (Marshall) e por amassamento (giros). Os resultados permitem concluir que, das misturas asfalticas recicladas estudadas, as mais adequadas para serem usadas em pavimentos flexiveis sao as que tem em sua composicao 10%, 15% e 20% de material fresado. Verificou-se, tambem, a influencia dos metodos de compactacao no comportamento mecânico das misturas asfalticas recicladas, uma vez que a compactacao por giros diminuiu substancialmente o volume de vazios das misturas. Palavras-chaves: Material fresado, Marshall, Superpave, Resistencia a tracao, Modulo de Resiliencia. MECHANICAL BEHAVIOUR OF RECYCLED ASPHALT MIXTURES USING COMPACTION BY IMPACT AND BY COMPRESSION ABSTRACT The necessity of a sustainable development makes researchers and road agencies search for alternatives that bring benefits not only on the environmental sector but also to the social and economic as well. The utilization of the resultant material from the cutted deteriorated pavement overlay incorporated to the new mixtures instead of the new compounds contributes to the asphalt recycling process. This solution minimizes the misuse of non renewable natural resources, gives a proper destination to the residues, besides achieving expenses deduction on the recovery and maintenance of the road network. The goal of this paper is to study the mechanical behavior of the recycled asphaltic mixtures containing cutted material in different proportions: 5%, 10%, 15%, 20%, 25% and 30%. To achieve the purpose, trials of tensile strength and resilient modulus, compacted by impact (Marshall) and by compression (gyrations) were performed. The results reveal that from the studied recycled asphaltic mixtures, the most suitable to be used on flexible pavement are the ones with 10%, 15% and 20% of cutted material. It was also noticed the influence of the compaction methods in the mechanical behavior of the recycled asphaltic mixtures, once that gyrations compaction highly decreased the amount of vacant mixtures. Keywords: Cutted material, Marshall, Superpave, Tensile strength, Resilient modulus.

Estudo da incorporação de argilas montmorilonitas em cimentos asfálticos de petróleo

A utilizacao de nanotecnologia em pavimentos asfalticos e uma revolucao, pois esta permite construir pavimentos mais resistentes a deformacao, a trinca por fadiga, a trinca por temperatura e a acao da agua.Nesse contexto uma alternativa e o uso da nanoargila. Sua incorporacao ao cimento asfaltico de petroleo (CAP) proporciona melhoria nas propriedades fisicas e reologicas e nas propriedades mecânicas das misturas asfalticas. Para o desenvolvimento deste trabalho utilizou-se o metodo da dosagem SUPERPAVE para a analise do comportamento das misturas asfalticas utilizando o CAP 50/70 modificado com as seguintes adicoes: Argila Montmorilonita organofilica (OMMT) e a Argila Montmorilonita pura (MMT). Foram analisados os efeitos dos modificadores por meio de ensaios mecânicos de Resistencia a Tracao por Compressao Diametral e Modulo de Resiliencia, sendo todas as amostras submetidas ao processo de compactacao por amassamento. Os resultados indicaram que as adicoes das argilas OMMT e MMT as misturas asfalticas promoveram aumento no valor do Modulo de Resiliencia e da Resistencia a Tracao quando comparados ao ligante asfaltico sem modificador.

Evaluating the rheological effect of asphalt binder modification using soybean oil

Abstract Brazil is a highlight in the ranking of maize cooking oil production, which after consumption generates a significant amount of waste that the improper disposal of it, which could seriously affect the sewage pipes, groundwater, and soil. This research study the incorporation of 1%, 2%, and 3% of soybean (new and waste) in asphalt binder. The samples were analyzed by FTIR and frequency sweep tests. The results indicate that the optimum oil content is in the range of 1–2%, regardless of being new or residual. In the temperature sweep, it was found that the asphalt binder 55/75-E showed a smaller phase angle in all mixtures compared to the asphalt binder 50/70, thus having a better elastic recovery.

Rheological properties of hydroxide and calcium oxide nanoparticles in asphalt binder

ABSTRACT The authors aimed to study the incorporation of calcium hydroxide (hydrated lime) and calcium oxide (lime virgin) in nanodimensions in order to increase the durability of pavements and reduce permanent deformation damage. In this research the authors included, in order to achieve the proposed objectives, information contained in the current literature as well as laboratory tests. These results demonstrate that the addition of nanoparticulate agents to asphalt binder is effective alternative in an attempt to improve the properties thereof for use in paving, with calcium oxide or quicklime in a 5% strength modifier, which showed significant enhancements.

Warm asphalt mixtures produced with addition of CCBit

ABSTRACT There is a growing concern with the environmental damage caused by the various types of industrial activities. Because of that, research in paving has sought alternatives to reduce fuel consumption and emissions of greenhouse gases generated by those. The warm mixtures have received increasing attention because they are capable of decreasing the mixture and compaction temperatures of asphalt mixtures. The objective of this study was to evaluate the effect of the incorporation of CCBit from the mechanical characterization of asphalt mixtures. From the results, it was found that the incorporation of CCBit has the advantage of reducing mixing and compaction temperatures without harming their mechanical behavior.

Avaliação de um Solo em Termos de Resistência à Compressão Simples, Resistência à Tração por Compressão Diametral e Módulo de Resiliência, Considerando Resultados de Diferentes Tipos de Compactação

In Brazil, the laboratory testing of Proctor compaction is regulated by the Brazilian Association of Technical Standards (NBR 7182/1986) and the National Department of Infrastructure and Transport (DNIT - ME 164/2013 and DNIT - ME 162/1994). The standards show various alternatives for performing compaction Proctor, however, it appears that the mechanical behavior of a compacted soil is a function of void content, degree of saturation and especially soil structure directly influenced by the compaction process adopted. This study aimed to compare four different compactation processes (mechanical with reuse, manual with reuse, manual without reuse and manual without reused with wetting of the sample 24 hours prior to compactation) using the intermediate energy, with the intention of assessing their effect on properties of compressive strength, tensile strength and resiliency of a soil. The experimental phase was divided into three (3) stages: Soil characterization tests, Proctor compaction tests and mechanical tests (resistance to simple compression - RCS, Tensile Strength for Diametral Compression - RT and Resilience Module - MR). Through this research, it was found that the type of compactation used exerted a significant influence on the results, because in general the RT values, RCS and MR obtained in manual compactation without reuse 24h were higher than the other compactions.