Curing is a crucial process during the construction phase of concrete structures, as it plays a significant role in ensuring durability and strength. During the curing process, the concrete is kept moist to allow properly hydration and hardening. This process helps to prevent cracking, increase the concrete's compressive strength, and improve its resistance to weathering, abrasion, and other forms of wear. Therefore, it is essential that the curing process is carried out correctly to ensure the longevity and structural integrity of the concrete structures. The pore system within concrete plays a critical role in determining its durability and resistance to various types of degradation. One way to assess the quality and durability of concrete is by measuring its gas permeability. Gas permeability is a measure of how easily gases, such as air or water vapor, can pass through the concrete. If concrete has high gas permeability, it allows harmful substances, such as water, gases and chemicals, to penetrate into the concrete, causing damage and reducing its durability over time. Herein gas permeability testing is used for the evaluation of concrete curing quality.

This concept paper discusses the effects of the installation condition of fasteners on the life‐cycle performance of noise barriers. Noise barriers that are erected along high‐speed railway lines are loaded by aerodynamic pressure and suction waves due to the passing trains. As an integral part of railway infrastructures their level of safety must be maintained throughout their entire lifetime. On basis of this concept and study, a potential monitoring‐based approach for the assessment of the life‐cycle performance of NBs is briefly introduced. That monitoring‐based approach finds its place in a holistic four‐stage assessment framework, in other words a progressive four‐stage model in which the information content increases with each model stage and thus successively increases the accuracy of the determined structural conditions at the time of observation and the prediction for the remaining service life of the structure. The objectives of this paper should bring relevant insights for the whole holistic four‐stage model. Depending on how far the degradation of the considered noise barrier has already progressed, the corresponding stage of the holistic assessment concept is activated, which enable infrastructure managers to plan their future investments regarding maintenance, retrofit or rebuilt of noise barriers more economically.

Railway noise barrier constructions are subjected to high aerodynamic loads during the train passages, and the knowledge of their actual structural condition is relevant to assure safety for railway users and to create a basis for forecasting. This paper deals with deterministic and probabilistic approaches for the condition assessment and prediction of the remaining lifetime of railway noise barriers that are embedded in a safety concept that takes into account the damage consequence classes. These approaches are combined into a holistic assessment concept, in other words, a progressive four-stage model in which the information content increases with each model stage and thus successively increases the accuracy of the determined structural conditions at the time of observation and the forecast of the remaining service life of the structure. The analytical methods used in the first stage of the developed holistic framework are based on common static calculations used in engineering practice and, together with expert knowledge and large-scale fatigue test results of noise barrier constructions, form the basis for the subsequent stages. In the second stage of the data-driven condition assessment and life cycle analysis approach, linking routines are implemented that combine the condition assessments from the visual inspections with the additional information from temporary or permanent monitoring systems with the analytical methods. With the application of numerical finite element methods for the development of a digital twin of the noise barrier in the third stage and the probabilistic approaches in the fourth stage, a maximum determination accuracy of the noise barrier condition at the time of observation and prediction accuracy of the remaining service life is achieved. The data-driven condition assessment and life cycle analysis approach enables infrastructure operators to plan their future investments more economically regarding the maintenance, retrofitting, or new construction of railway noise barriers. Ultimately, the aim is to integrate the presented four-stage holistic assessment concept into the specific maintenance and repair planning of infrastructure operators for aerodynamically loaded railway noise barrier constructions.

The high safety requirements for railway infrastructures are a basic demand that the railway user places on the railway operator. Noise barriers that are erected along high-speed railway lines are loaded by aerodynamic pressure and suction waves due to the passing trains. Noise barriers are an integral part of railway infrastructures, and their level of safety must be maintained throughout their entire lifetime. This concept paper discusses deterministic and probabilistic-based approaches for condition assessment and prognosis of remaining service life of railway noise barriers, embedded in a safety concept that takes damage consequence classes into account. These approaches are combined into a holistic assessment concept, in other words a progressive four-stage model in which the information content increases with each model stage and thus successively increases the accuracy of the determined structural conditions at the time of observation and the forecast for the remaining service life of the structure. The analytical methods used in the first stage of the developed holistic framework are based on common static calculations used in the engineering practice and, together with expert knowledge and large-scale fatigue test results of noise barrier constructions, form the basis for the subsequent stages. Linking routines that combine the condition assessments from the common executed visual inspections and additional information from permanent monitoring systems applied to failure-critical elements with the analytical methods of the first stage are implemented in the second stage of the holistic framework. With application of numerical finite element methods in the third stage and finally the probabilistic approaches in stage four, the highest degree of determination accuracy of the noise barrier condition at the time of observation and prediction accuracy of the remaining lifetime shall be achieved. Depending on how far the degradation of the considered noise barrier has already progressed, the corresponding stage of the holistic assessment concept is activated, which enable infrastructure managers to plan their future investments regarding maintenance, retrofit or rebuilt of noise barriers more economically. The aim is to integrate the project results into a supranational framework, which is established through orientation towards Europe-wide preliminary projects.

Cyclic compression fatigue properties of concrete are studied with the ultrasonic fatigue testing method with cycling frequency 19 kHz and are compared to servo-hydraulic tests performed at 60 Hz. Ultrasonic testing was found applicable for rapid generation of very high cycle fatigue (VHCF) data of concrete. Fatigue cracks can be initiated, however specimens do not rupture, since cyclic stresses decrease with increase of compliance in displacement controlled ultrasonic tests. Observation of resonance frequency, analysis of higher order harmonics of vibration, and computed tomography of specimens are successful methods to analyse fatigue damage. Calorimetric evaluations can be used to calculate the cyclic irreversible strain, which is about 1% of the elastic strain in the ultrasonic VHCF test.