Sebnem Karahancer

The investigation of Polyamide fiber as an additive in HMA

The number of heavy vehicles on traffic and traffic volume are extremely increasing nowadays. Consequently, maintenance costs are increasing too. So, durability becomes necessary in asphalt pavement design and construction. For this purpose, asphalt industry partners are investigating innovative technologies and additives for Hot Mix Asphalt (HMA) Pavements. In this study, the utility of Polyamide 6.6, which is a synthetically produced flexible and highly thermoplastic material that have good mechanical and physical properties in terms within the nylon species, was investigated in HMA as a fiber. For examining the test results, specimens were prepared in four different proportions including reference specimens. Volumetric mix design was used to determine the optimum bitumen content. Then Indirect Tensile Strength (ITS) Test was applied to HMA specimens. The aim of this research was to identify the usability of Polyamide 6.6 in HMA mixtures as a fiber, and the engineering properties of the specimens with Polyamide 6.6 fiber.

Increasing the visibility of roads using phosphorous paint

Lighting the roads and so increasing the visibility is very important to avoid accidents. In this study, an acrylic and UV-react phosphorous paint (PP) is added to the hot mix asphalt for improving the visibility of the pavement. PP has been added to the mixture while blending binder with the mineral aggregates, based on six different ratios (15%, 20%, 25%, 30%, 35% and 40% by weight of binder). Specimens are compacted with the Superpave Gyratory Compactor according to the volumetric mix design. Compacted specimens are photographed in a dark box under UV light and the change in visibility ratio is analysed with a software. Compacted specimens are analysed with an image analysing software to obtain the change in the visibility. PP-added specimens are tested in accordance with AASHTO T283 to obtain the indirect tensile strength and tensile strength ratio values to determine whether the minimum specification limits are ensured. As a result, by adding the PP, the visibility ratio of the specimens is increased. Best visibility rate is achieved by 35–40% PP additive.

Modelling Marshall Stability of fiber reinforced asphalt mixtures with ANFIS

In this study, an Adaptive Neural Fuzzy Inference System (ANFIS) model for predicting the Marshall Stability (MS) of basalt fiber reinforced asphalt concrete mixtures and various mix proportions has been developed. Experimental details were used to construct the model. The amounts of bitumen (%), Fiber (Basalt) Ratio (%) were used as input variables and Marshall Stability (kg) values were used as output variables. Statistical equations were used to evaluate the Developed ANFIS model. Results showed that developed ANFIS model has strong potential to predict Marshall Stability of asphalt concrete using related inputs in a short time. Also, the Marshall Stability of Fiber-Reinforced asphalt concrete and various mix proportions can be found without performing any experiments.

Marshall stability estimating using artificial neural network with polyparaphenylene terephtalamide fibre rate

Due to the complex behaviour of asphalt pavement materials under various loading conditions, pavement structure, and environmental conditions, accurately predicting stability of asphalt pavement is difficult. To predict, it is required to find the mathematical relation between the input and output data by an accurate and simple method. In recent years, artificial neural networks (ANNs) have been used to model the properties and behaviour of materials, and to find complex relations between different properties in many fields of civil engineering applications, because of their ability to learn and to adapt. In the present study, laboratory data are obtained from an experimental study that was used to develop an ANN model. For predicting the Marshall Stability value of mixture using ANN models, an appropriate selection of input parameters (neurons) is essential. There are four nodes in the input layer corresponding to four variables: Polyparaphenylene Terephtalamide fibre (PTF) rate, binder rate, flow, volume of the specimen. The result indicates that the proposed model can be applied in predicting Marshall Stability of asphalt mixtures. The model is further applied to evaluate the effect of different rates of Polyparaphenylene Terephtalamide on Marshall Stability.

Investigation of Using Waste Welded Tuff Material as Mineral Filler in Asphalt Concrete

In this paper, the welded tuff waste- known as koyke in Isparta region - was used in the hot mix asphalt (HMA) as mineral filler for reduction of the moisture susceptibility of HMA. Optimum binder content was assessed with Marshall Design Method. First of all, welded tuff was substituted as filler with limestone filler in proportion of 50% and 100%. After that Marshall Stability test was performed on specimens. The results showed that the 50% substitution was more effective than the 100% substitution. Therefore, welded tuff was substituted with limestone filler in proportion of 25%, 50%, 65% and 75%. Next, Indirect Tensile Strength test was practiced on the fabricated specimens and the results were assessed. According to the Indirect Tensile Strength results, welded tuff with 65% was given higher strength than the limestone filler. As a result, it has come up that welded tuff can be used as mineral filler in the hot mix asphalt.

Plasma Empowered Limestone Composite Structures for Asphalt Performance Applications

The motivation of this study is using plasma modification to significantly increase the performance of the hot mix asphalt. The surface of mineral filler was modified by using three different components: tungsten disulphide under peroxide (WS2 – H2O2), tungsten disulphide under water (WS2 – H2O) and silicon dioxide (SiO2) nano powders. Hot mix asphalts prepared with plasma modified mineral fillers were evaluated by Marshall Stability (MS) test. According to the results of modified SiO2 plasma samples were showed higher stabilities and better properties. Eco-friendly plasma modification technique provided homogenous, single step and fast processing for the modification of the asphalt materials.