Coal ash produced from thermal power plants as a substitute for conventional construction material has increased considerably in recent years. In the past, studies on partial replacement of soil were carried out with a single type of ash. Because of the insufficient evidence, limited research has been initiated on the productive usage of Fly and Bottom Ashes. This paper aims to study the properties of these materials and investigate their efficacy in road construction. Laboratory investigations were conducted to assess chemical and physical properties and mechanical performance to evaluate both ash types in pavement construction. The rutting factor is calculated for various combinations of coal ash materials with the addition of polypropylene fiber as a reinforcement in increments of 0.1% of its total weight with an aspect ratio of 200. The analytical tool ANSYS is used to validate the service life, vertical strain and quality of reinforced ash materials.

Predicting the aging process of residential buildings carried out using traditional technologies is necessary when planning refurbishment works in these buildings. The article presents a picture of the changes in the technical condition of a not refurbished building constructed in traditional technology, in the form of a function describing the aging process according to the PRRD (Prediction of Reliability according to Rayleigh Distribution) model developed by the author. The results of analyses of the relationships between the function of the intensity of damage and the function of unreliability, as well as the function of changes in the performance characteristics of a building which had not undergone refurbishment during the entire course of its use are presented. Three levels of damage intensity during subsequent years of using the building were determined: safe, critical and unacceptable intensity.

Accordingly to recommendations set out by standards, degradation curves which will serve as a tool facilitating decision-making regarding renovation works ought to be developed. The article presents the proposal of a model for predicting the aging of a residential building. The proposed PRRD (Prediction of Reliability According to Rayleigh Distribution) model determines the performance characteristics of a building over the full period of its use. PRRD accounts for the life spans of individual building components. Additionally introduced in the model were supplements accounting for the intensity of changes in the building and its surroundings. The developed method of the non-linear degradation process of a building accounts for the role and weights of individual building components as well as the intensity of significant factors influencing the aging process. The presented methodology of the description of changes in the performance characteristics over the course of using a building will be a diagnostic process of predicting the technical state of a building. The proposed predictions can serve as the basis for making the right strategic decisions when planning renovation works in residential buildings.

The current fatigue evaluation procedures in Europe and North American bridge codes do not account for the degree of uncertainty in load and resistance models. However, the variability of cycling loading and material properties have a significant influence on fatigue safety verification. A fatigue verification is contingent on the accumulated load cycles and the fatigue category; which, in turn, depends on member type and its connections. Assessment of structural safety can be evaluated more completely using probabilistic methods that provide fatigue prediction in terms of the probability of crack initiation. This method provides more information about the expected performance of a structural component; therefore, the structure can be used in service for a significantly longer time. In this article, the comparison of fatigue evaluation is presented using Eurocode, North American Standard – AREMA, and the new approach using the probabilistic method. These methods are demonstrated on the riveted built-up beams of the steel deck plate girder (DPG) railway bridge using data from field monitoring.