In the recent years structural health monitoring (SHM) has gathered spectacular attention in civil engineering applications. Application of such composites enable to improve the safety and performance of structures. Recent advances in nanotechnology have led to development of new family of sensors – self-sensing materials. These materials enable to create the so-called “smart concrete” exhibiting self-sensing ability. Application of selfsensing materials in cement-based materials enables to detect their own state of strain or stress reflected as a change in their electrical properties. The variation of strain or stress is associated with the variation in material’s electrical characteristics, such as resistance or impedance. Therefore, it is possible to efficiently detect and localize crack formation and propagation in selected concrete element. This review is devoted to present contemporary developments in application of nanomaterials in self-sensing cement-based composites and future directions in the field of smart structures.
The rheological properties of self-compacting concrete are closely influenced by temperature and the time. Previous studies which aim was to research the effect of temperature on self-compacting concrete workability, showed that the behaviour of fresh SCC at varying temperatures differs from that of normal vibrated concrete. The paper presents the study of rheological properties of fresh self-compacting concrete mixtures made with portland, blast furnace and component cement. Two types of superplasticizers were used. It was proven that temperature has a clear effect on workability; it can be reduced by selecting the appropriate superplasticizer and cement.
Self-curing concrete SC is a concrete type that can be cured without using any external curing regimes. It can perform by several methods such as using lightweight aggregate or chemical agents. In this research chemical curing agent is used to produce SC. This paper reports the results of a research study conducted to evaluate the effect of sulfates on the performance of self-curing concrete compared to ordinary concrete. Samples are immersed in sodium sulfate Na2S04 solution of 4% concentration. Results are measured in terms of compressive strength, tensile strength, flexural strength and mass loss. It was found that the rate of strength loss is noticed at ordinary concrete compared to SC concrete. Sulfate resistance is improved when using self-curing concrete. This improvement appears to be dependent on using a chemical curing agent.
This paper presents research results of composite tubes filled with self-compacting concrete. The impact of the selected materials and geometric factors on resistance to the vertical shear was evaluated in this study. The resistance of the tested members was compared with recommendations given in Eurocode PN-EN 1994-1-1. From the results obtained in the tests it can be deduced that more parameters should be taken into consideration when determining resistance to the vertical shear in the interface between steel and concrete than PN-EN 1994-1-1 recommends.
Nowadays, self-climbing formworks are commonly used in the construction of concrete buildings with a great height, such as high-rise buildings, silos, and bridge piers. A regular formwork can be improved to have more functions, e.g., the formwork itself can climb to the desired construction site. Climbing characteristics of the formwork as well as opening and closing characteristics of the formwork shell are essential criteria for evaluating the performance of a self-climbing formwork. The effective ones were mentioned in different studies, where most of them were published in patents of countries, e.g., the United States and China. Dissimilar from these studies, this paper presents several improvements for some certain groups to enhance the features of a hydraulic self-climbing formwork. Based on the analysis of the composition and the working principle of the actual climbing formwork types, a new opening and closing method of the formwork shells and a new rail clamping device are suggested. They are applied to design a self-climbing formwork with the shell’s working size of 4 m x 3 m. Their load capacity, as well as the flatness of the concrete surface after casting, are assessed. The proposed solutions can result in various advantages, e.g., the shorter initial alignment time, the increase of the quality concrete surface, and the maximal automation for construction operations.
Light-weight Self-Compacting Concrete (LWSCC) might be the answer to the increasing construction requirements of slenderer and more heavily reinforced structural elements. However there are limited studies to prove its ability in real construction projects. In conjunction with the traditional methods, artificial intelligent based modeling methods have been applied to simulate the non-linear and complex behavior of concrete in the recent years. Twenty one laboratory experimental investigations on the mechanical properties of LWSCC; published in recent 12 years have been analyzed in this study. The collected information is used to investigate the relationship between compressive strength, elasticity modulus and splitting tensile strength in LWSCC. Analytically proposed model in ANFIS is verified by multi factor linear regression analysis. Comparing the estimated results, ANFIS analysis gives more compatible results and is preferred to estimate the properties of LWSCC.
Przedmiotem rozważań jest koncepcja self-blindness. Autorka definiuje jąprzez eksperyment myślowy przedstawiający sytuację, w której osoba pomimo zachowania zdolności poznawczych i racjonalności nie ma bezpośredniego dostępu do własnych przekonań. Przywołuje również uporządkowane przez siebie argumenty przeczące możliwości istnienia takiej sytuacji. Pod koniec artykułu stara się wskazać wartościowe wnioski i drogi dalszych rozważań bazujące na tej koncepcji – dotyczące mechanizmów dostępu do przekonań oraz ich natury.
The presented article points to the issues of self-consciousness and the possibilities of its development. It defines in this context also concepts of self-evaluation, self-respect, self-appreciation, self-recognition, self-confidence and self-realization. In the text, it is emphasized that self-consciousness is related to the awareness of one´s own psychophysical and social identity - I myself and the world and my place in it. An important means for the development of the healthy self-consciousness is also praise. In the conclusion of the article, attention is paid to the psycho-hygiene as prevention of the failure.
Four types of self-standards (ideal, ought, undesired, and forbidden selves) were analyzed in the context of self-assessed health of older adults. We focused on the relationships between self-discrepancies (perceived actualization of self-standards) and affect, as well as the content of self-descriptions of standards. Participants (116 Polish older adults) completed: Self Standards’ Measure (SSM), PANAS-X and 7 items from the WHOQOL-BREF. First, we found that self-assessed health moderates the effects of self-discrepancies on affect. The ideal and ought self-discrepancies predicted affect when health was assessed as good. Conversely, the undesired and forbidden self-discrepancies predicted affect when health was assessed as poor. Second, health-related content was more typical for the ideal than for the ought standards. Third, older adults who assessed their health better had fewer health-related standards. The results are discussed with reference to control theory of approach and avoidance.
This paper aims at elaborating the concept of linguistic self with regard to its twofold existence modes, namely as a physical person and as a mental subject, being shaped by external and internal dialogs in interpersonal and intersubjective communication. These dialogical encounters, constantly changing the reality of everyday life, are based, on the one hand, on the observable multitextuality of narratives, and on the other, on the multi-voicedness of opinions. As such, it lays emphasis on the need for a holistic approach to human beings as a psychosomatic unity, taking part in cognition with their minds and bodies, and developing itself both in-and-with the physical and logical domains of their surrounding ecosystems. In view of the private and public character of the self, the author postulates to consider in future studies the achievements of personal and social constructivism.
In general, it is ben eficial and adaptive to have high self-esteem; however, contingent self-esteem depending on approval is not so advantageous. This article presents research on a Polish version of the Contingent Self-Esteem Scale (CSES), which measures contingent self-esteem. The CSES was administered on a total of 1,199 participants; a range of other instruments were also used to establish the validity of the CSES. The CSES proved to have acceptable internal consistency and validity and factor analyses revealed that it contains four factors: vulnerability to negative opinions, dependence on physical attractiveness, dependence on opinions, and dependence on self-standards. Contingent self-esteem was positively correlated with neuroticism, agreeableness, ruminating, anxiety, and maladaptive perfectionism; it was negatively correlated with general self-esteem and self-efficacy. Mediational analyses confirmed the hypothesis that low general self-esteem causes high rumination about oneself, which in turn is related to high contingent self-esteem.