Fiber reinforced concrete: Tailoring composite properties with discrete fibers

Concrete is one of the most widely used building materials in the world. The single largest limitation of concrete is its weak and brittle nature under tensile stress. In order to improve this material behavior, reinforcement materials that are strong in tension are embedded into the concrete to avoid brittle failure and increase tensile load capacity. Besides the traditional methods of embedding continuous aligned reinforcement in anticipated zones of tensile stress, random discrete fibers can be dispersed into the concrete during the mixing procedure to create a composite material called fiber reinforced concrete (FRC). In this study, a comprehensive review of the relevant and recent literature pertaining to FRC is provided, establishing basic principles and highlighting the possible contributions to composite properties that different types of fiber can deliver. Once the capabilities and limitations of FRC are well established from previous works, an experimental investigation is conducted, in which flexural testing of 3 different types of synthetic concrete fibers was performed to determine their performance in the fresh state as well as hardened state under flexural loading. The experimental work is then extended to investigate how carbon microfibers and concrete admixtures affect concrete strength development and shrinkage behavior for applications in which high early age strength and shrinkage control is desired. The outcome of this study is anticipated to contribute to the state of FRC knowledge and practice by providing important findings from previous work, supplemented by experimental data which effectively highlights the capabilities that the addition of discrete fibers can impart to concrete

Flourishing in nature: A review of the benefits of connecting with nature and its application as a wellbeing intervention

From the increasing number of people living in urban areas to the continued degradation of the natural environment, many of us appear to be physically and psychologically disconnected from nature. We consider the theoretical explanations and present evidence for why this state of affairs might result in suboptimal levels of hedonic and eudaimonic wellbeing by reviewing the large body of research on the mental health benefits of connecting with nature. The advantages of contact with nature as a potential wellbeing intervention are discussed, and examples of how this research is being applied to reconnect individuals to nature and improve wellbeing are given. We conclude by considering the limitations of, and proposing future directions for, research in this area. Overall, evidence suggests that connecting with nature is one path to flourishing in life

State-of-the-Art Review of Capabilities and Limitations of Polymer and Glass Fibers Used for Fiber-Reinforced Concrete

The concrete industry has long been adding discrete fibers to cementitious materials to compensate for their (relatively) low tensile strengths and control possible cracks. Extensive past studies have identified effective strategies to mix and utilize the discrete fibers, but as the fiber material properties advance, so do the properties of the cementitious composites made with them. Thus, it is critical to have a state-of-the-art understanding of not only the effects of individual fiber types on various properties of concrete, but also how those properties are influenced by changing the fiber type. For this purpose, the current study provides a detailed review of the relevant literature pertaining to different fiber types considered for fiber-reinforced concrete (FRC) applications with a focus on their capabilities, limitations, common uses, and most recent advances. To achieve this goal, the main fiber properties that are influential on the characteristics of cementitious composites in the fresh and hardened states are first investigated. The study is then extended to the stability of the identified fibers in alkaline environments and how they bond with cementitious matrices. The effects of fiber type on the workability, pre- and post-peak mechanical properties, shrinkage, and extreme temperature resistance of the FRC are explored as well. In offering holistic comparisons, the outcome of this study provides a comprehensive guide to properly choose and utilize the benefits of fibers in concrete, facilitating an informed design of various FRC products.This article is published as Shafei, Behrouz, Maziar Kazemian, Michael Dopko, and Meysam Najimi. "State-of-the-art review of capabilities and limitations of polymer and glass fibers used for fiber-reinforced concrete." Materials 14, no. 2 (2021): 409. doi: https://doi.org/10.3390/ma14020409. © 2021 by the authors. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)

Nature connectedness: Associations with well-being and mindfulness

a b s t r a c t Wilson's (1984) biophilia hypothesis predicts that people's psychological health is associated with their relationship to nature. Two studies examined associations among nature connectedness, well-being, and mindfulness in samples of undergraduate students while socially desirable responding was controlled. Significant associations emerged among measures of nature connectedness and indices of wellbeing (in Study 1 and Study 2) and mindfulness (in Study 2). Results are discussed in relation to possible mediators and moderators of the association between nature connectedness and mental health

Fiber reinforced concrete: Tailoring composite properties with discrete fibers

Concrete is one of the most widely used building materials in the world. The single largest limitation of concrete is its weak and brittle nature under tensile stress. In order to improve this material behavior, reinforcement materials that are strong in tension are embedded into the concrete to avoid brittle failure and increase tensile load capacity. Besides the traditional methods of embedding continuous aligned reinforcement in anticipated zones of tensile stress, random discrete fibers can be dispersed into the concrete during the mixing procedure to create a composite material called fiber reinforced concrete (FRC). In this study, a comprehensive review of the relevant and recent literature pertaining to FRC is provided, establishing basic principles and highlighting the possible contributions to composite properties that different types of fiber can deliver. Once the capabilities and limitations of FRC are well established from previous works, an experimental investigation is conducted, in which flexural testing of 3 different types of synthetic concrete fibers was performed to determine their performance in the fresh state as well as hardened state under flexural loading. The experimental work is then extended to investigate how carbon microfibers and concrete admixtures affect concrete strength development and shrinkage behavior for applications in which high early age strength and shrinkage control is desired. The outcome of this study is anticipated to contribute to the state of FRC knowledge and practice by providing important findings from previous work, supplemented by experimental data which effectively highlights the capabilities that the addition of discrete fibers can impart to concrete.</p

„Z pamiętnika siostry zakonnicy” i inne przygody duszy w małych prozach Gabrieli Zapolskiej

Do dziś twórczość XIX-wiecznej pisarki, Gabrieli Zapolskiej, znanej przede wszystkim z Moralności Pani Dulskiej, wzbudza wiele emocji. Nadal uważa się ją wyłącznie za buntowniczkę i skandalistkę, która nie zwracała uwagi na sprawy duchowe i nie poruszała w swojej twórczości tematów związanych z wiarą. Przedmiotem analiz zaprezentowanych w artykule są trzy utwory Gabrieli Zapolskiej o charakterze religijnym, w tym praktycznie nieznany pt. Z pamiętnika siostry zakonnicy.</jats:p