Thermally modified (TM) beech wood: compression properties, fracture toughness and cohesive law in mode II obtained from the three-point end-notched flexure (3ENF) test

[EN] The fracture properties of thermally modified beech (Fagus sylvatica) wood (TMW) at 180 degrees and 200 degrees C were evaluated in mode II using the three-point end-notched flexure (3ENF) scheme assisted by three-dimensional (3D) stereovision equipment for obtaining displacements and strains. The compliance-based beam method (CBBM) provided the strain energy release rates (G(II)) of TMW and cohesive laws for both native wood (W) and TMW. Based on the CBBM and equivalent crack length approach (ECLA), G(II) was obtained directly from the force-deflection data. The thermal modification (TM) process reduced the compressive strength by 4.4% and increased the compressive elastic modulus by 38.3%, whereas G(II) was reduced substantially by 40.8% and 67.9% at TM180 degrees C and TM200 degrees C, respectively. TM also increased wood brittleness that was visible on the displacement slip reduction. The resulting mean cohesive models can be used for numerical analyses. The fracture properties of TMW have to be taken into consideration for constructional wood application, when cyclic loading may lead to microcracking and material fatigue.The authors would like to thank COST Action FP1407 (Funder Id: https://dx.doi.org/10.13039/501100000921), the European Commission for funding the InnoRenew CoE project under the Horizon2020 Widespread-Teaming program (grant agreement #739574), the Republic of Slovenia for providing support from the European Regional Development Funds, and the financial support provided by the Internal Grant Agency (IGA) of the Faculty of Forestry and Wood Technology, Mendel University in Brno (LDF_PSV_2016015).Sebera, V.; Redón-Santafé, M.; Brabec, M.; Decky, D.; Cermak, P.; Tippner, J.; Milch, J. (2019). Thermally modified (TM) beech wood: compression properties, fracture toughness and cohesive law in mode II obtained from the three-point end-notched flexure (3ENF) test. Holzforschung. 73(7):663-672. https://doi.org/10.1515/hf-2018-018866367273

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Analysis of Selected Pavement Serviceability Parameters

The parameters of pavement serviceability have the notable effect to the road life time and to the conditions of safe and comfortable driving. The serviceability of flexible pavements is defined by three parameters: skid resistance, unevenness and pavement distress. The Slovak Road Administration observes 24 specific road sections on which the parameters have been measured two times per year since 1998. The obtained data should be used for determination of the degradation models that describe the qualitative decreasing of the parameters depending on time and traffic load. The functions are very important for definition of the optimal road maintenance and rehabilitation. The degradation models describing the parameters changes over time are the substantial research problem in dependence on many affecting factors.The results of pavement serviceability parameters evaluation are presented in the paper. The basic functions are described and discussed

Project Spens - Sustainable Pavement for European New Member States

This paper represents the main results of work package 5 of the SPENS project (Sustainable Pavements for European New Member States) that was focused on assessment of the impact of roads on the environment and where the Faculty of Civil Engineering of University of Zilina was the most active and closely cooperated with CDV.Collaborative international project was focused on particulate matter (PM) production due to mechanical abrasion of road pavements. PM (and noise emission) was captured next to roads with different pavement types (stone mastic asphalt and asphalt concrete) by middle volume samplers with consequent gravimetric analysis of each exposed filter. The content of organic and inorganic pollutants fixed to PM was determined to characterise the PM composition. Dust fall measurements including mass and chemical composition determination in road tunnels with different pavements (cement concrete and asphalt concrete) were done to determine the pavement abrasion contribution to overall PM emissions in tunnels

Sustainable Adaptive Cycle Pavements Using Composite Foam Concrete at High Altitudes in Central Europe

Climate pavement adaptability is an integral part of a holistic concept of road design, construction, and pavement management. One of the possibilities for fulfilling the mentioned author’s premise in sustainable cycle pavements in the cold region of Central Europe is using composite foam concrete (CFC). To establish the credibility of the design of these pavements, we objectified the correlation dependencies of average annual air temperatures and frost indexes, for altitude regions from 314 to 858 m in the period 1971 to 2020, at its height above sea level. As part of the research on the increase in tensile strength during bending of CFC, extensive laboratory measurements were carried out and validated by isomorphic models of real roads, which enabled an increase in tensile strength during bending from 0.376 to 1.370 N·mm−2 for basalt reinforcing mesh. The research results, verified through FEM (Finite Element Method) models of cycle pavements, demonstrated a possible reduction of total pavement thickness from 56 to 38 cm for rigid pavements and 48 to 38 cm for flexible pavements

The World’s Oldest Pavements and in the Town Žilina Into the Context Within Municipal Engineering

In this article, the authors explore examples of preserved cultural heritage related to traffic structures, focusing on the world's oldest bridges in Europe and Slovakia, as well as the oldest preserved roadways. They delve into the detailed history of Marians Square in Žilina, particularly its surface treatment, drawing from credible historical sources. The article also presents comparisons of elasticity modules and deformations of the roadway, based on measurements taken in 1966 and the last reconstruction from 1995 to 1997, which cost SK 64.5 million (equivalent to EUR 6.9 million in 2024). Through an evaluation of mechanical characteristics and environmental criteria, the authors conclude that the reconstructed road, even in 2024, effectively protects against frost damage, minimizes particulate matter and noise pollution (excluded motor traffic), and adheres to principles of contextual design for pavements

Evaluation of the Effect of Average Annual Temperatures in Slovakia between 1971 and 2020 on Stresses in Rigid Pavements

The scientific community in Central Europe often discusses the extent to which temperature changes over the last two decades have contributed to changing the stresses induced in structures. In the field of road and environmental engineering, this question is especially pertinent for pavements. The pavement structure must first be defined methodologically by identifying and defining the types of parameters that change with time. Additionally, it is important to identify the areas of Central Europe that are most affected by climate change. The most important parameters must be described statistically for these areas. Slovakia is one of the countries that may be able to contribute to the solution of this issue due to its location in the middle of Europe. This paper provides a statistical analysis for the period from 1971 to 2020 in Slovakia. A concrete pavement, which is the most commonly used type of pavement, must be used as an example to numerical assess the situation. The conclusions and discussion in this scientific field are directed towards the evaluation of the measurement results in the context of the designed pavement composition and the calculations using the different methods specified in the standards

Sustainable Adaptive Cycle Pavements Using Composite Foam Concrete at High Altitudes in Central Europe

Climate pavement adaptability is an integral part of a holistic concept of road design, construction, and pavement management. One of the possibilities for fulfilling the mentioned author’s premise in sustainable cycle pavements in the cold region of Central Europe is using composite foam concrete (CFC). To establish the credibility of the design of these pavements, we objectified the correlation dependencies of average annual air temperatures and frost indexes, for altitude regions from 314 to 858 m in the period 1971 to 2020, at its height above sea level. As part of the research on the increase in tensile strength during bending of CFC, extensive laboratory measurements were carried out and validated by isomorphic models of real roads, which enabled an increase in tensile strength during bending from 0.376 to 1.370 N·mm−2 for basalt reinforcing mesh. The research results, verified through FEM (Finite Element Method) models of cycle pavements, demonstrated a possible reduction of total pavement thickness from 56 to 38 cm for rigid pavements and 48 to 38 cm for flexible pavements

Pavement Diagnosis as Integrant of the Pavement Management System

The paper integrates the most important scientific information of the authors in the field of diagnostics of road pavements. Basic attributes of pavement serviceability (evenness, skid resistance) and pavement bearing capacity are the core of the paper. The results of simulations of dynamic systems, outputs of the models developed at the authors place, the correlations to the world established parameters of evenness and skid resistance are presented in the paper. Objective scientific outputs have formed an effectual base for development the Slovak Pavement Management System (PMS). The principles of the Slovak PMS are described

Evaluation of the Effect of Average Annual Temperatures in Slovakia between 1971 and 2020 on Stresses in Rigid Pavements

The scientific community in Central Europe often discusses the extent to which temperature changes over the last two decades have contributed to changing the stresses induced in structures. In the field of road and environmental engineering, this question is especially pertinent for pavements. The pavement structure must first be defined methodologically by identifying and defining the types of parameters that change with time. Additionally, it is important to identify the areas of Central Europe that are most affected by climate change. The most important parameters must be described statistically for these areas. Slovakia is one of the countries that may be able to contribute to the solution of this issue due to its location in the middle of Europe. This paper provides a statistical analysis for the period from 1971 to 2020 in Slovakia. A concrete pavement, which is the most commonly used type of pavement, must be used as an example to numerical assess the situation. The conclusions and discussion in this scientific field are directed towards the evaluation of the measurement results in the context of the designed pavement composition and the calculations using the different methods specified in the standards