Thai Cultivated Banana Fibers as The Sustainable Sound and Heat Insulation Materials

This study was aimed to develop on the sound absorber and the heat insulator derived from natural fiber (cultivated banana fiber) to be an alternative way. Normally, the community consume this equipment derived from synthetic materials (asbestos and fiberglass) which cause of the negative human health. The process of specimen preparation was started by the banana stem cutting-off step to prepare banana fibers which had been determined to slit of 2-3 mm fiber diameter by cutter and then dehydrated on these banana fibers. Eventually, a high-speed of grinder was applied to mill these fibers and then the 30 US MESH size of filter was utilized to 0.6 mm reducing fiber length. Therefrom, this cultivated banana fiber was prepared to test on Noise Reduction Coefficient (NRC) and Thermal Conductivity (TC) according to various factors: (1) banana fiber-gypsum ratio on 2:8 and 3:7 by weight, (2) banana fiber length of 0.6 mm and (3) 25.0 mm thickness of each specimen. These experiments were determined on the NRC value based on ISO10534-2 standard at frequency range 250-4,000 Hertz and the TC value based on ASTM C518 standard. In addition, the structural and scattering images of banana fiber and surface were investigated by Scanning Electron Microscope (SEM). The NRC result showed as 0.52 of banana fiber specimen in the length of 0.6 mm and banana fiber-gypsum ratio on 3:7 by weight that appeared more porosity and space area. Likewise, the TC result was found at 0.063 W/m.K. Consequently, this local natural material prepared by cultivated banana fiber was proven effective in noise reducing and heat-insulating purposes for Thailand’s community.Keywords: Cultivated Banana Fiber; Noise Reduction Coefficient; Thermal Conductivit

Towards sustainable micro and nano composites from fly ash and natural fibers for multifunctional applications

Manufacturing of petroleum based synthetic materials, exploitation of timber products from forest reserves, improper management of industrial wastes and natural resources greatly persuade the environmental contaminations and global warming. To find viable solutions and reduce such alarming issues, innovative research work on recycling of unutilized materials such as fly ash and natural cellulosic polymers has been reported in this work to develop advanced sustainable hybrid micro/nano composites. In this study, the use of natural cellulosic sisal fibers with fly ash has enhanced the tensile properties and surface finish of composites. Fly ash particulates acted as fillers, additives, as well as surface-finishing medium and sisal fibers as reinforcing elements in achieving glossy finish sustainable composites. The developed composites have been found to be stronger than wood, plastics and have many opportunities for multifunctional applications

Influence of calcium carbonate on green self-compacting concrete incorporating porcelain tile waste as coarse aggregate replacement

The disposal of ceramic tile waste poses a significant environmental challenge in the construction industry. This study aims to explore the influence of calcium carbonate (CC) on the properties of self-compacting concrete (SCC) incorporating porcelain tile waste as a coarse aggregate replacement. The objective is to enhance the performance of SCC while addressing the limitations of recycled ceramic aggregates and achieving the desired strength class. SCC specimens were cast by partially and completely substituting natural crushed rock with varying percentages of porcelain tile aggregates (PTA-0, 25 %, 50 %, 75 %, and 100 %) and cement with calcium carbonate (CC-10 %, 20 %, and 30 %). Workability assessments, mechanical properties, and durability were evaluated and compared against those of reference concrete. The experimental findings revealed that the incorporation of CC and PTA positively influenced the workability, mechanical properties and durability of SCC. Notably, the SCC mixture incorporating 10 %CC and 25 %PTA demonstrated exceptional performance, achieving the highest compressive strength of 64.9 MPa at 28 days. Moreover, even with complete substitution, the compressive strength reduction remained below 5 %. These results highlight the potential of PTA and CC-based SCC mixtures as an efficient and sustainable approach for utilizing porcelain tile waste in high performance concrete production. The findings contribute to addressing environmental concerns, promoting waste management practices, and reducing the reliance on natural resources in the construction industry

Recycling prestressed concrete pile waste to produce green self-compacting concrete

Construction and demolition waste is produced in large quantities and constitutes an overlooked resource with significant potential for recycling and reuse. In fact, recycled concrete aggregate (RCA) has a high resource value, although it is also the case that RCA has characteristics that complicate its reuse. This research study looks at the efficacy of producing green self-compacting concrete (SCC) using uniform in-situ prestressed concrete pile waste (RCA) as a replacement for natural aggregate and fly ash (FA) as a replacement for Type 1 Portland cement (OPC). In accordance with the European standard, the workability characteristics of the SCC mixtures were assessed using slump flow, T500 time, J-ring flow, L-box, and V-funnel tests. The hardened properties of compressive strength at 7, 28, and 91 days as well as pulse velocity, Young's modulus, and surface resistivity were also tested. Based on this study, it is possible to produce SCC with both RCA and FA that has better workability and hardened properties than does RCA and also to reduce the negative effects of the latter. SCC produced without coarse natural aggregates showed compressive strength above 50 MPa and maximum compressive strength above 74 MPa at 91 days. SCC produced in this way is, therefore, viable for industrial use

Characteristics of non-steady-state chloride migration of self-compacting concrete containing recycled concrete aggregate made of fly ash and silica fume

Chloride migration poses a significant challenge to the long-term durability of concrete structures due to its potential to corrode reinforcement and deteriorate the structure. This study focuses on chloride migration in self-compacting concrete (SCC) made with pozzolans, namely silica fume (SF) and fly ash (FA), along with recycled concrete aggregate (RCA). Particularly, the effects of external electrical potential (power-on) duration and RCA content on the features of SCC were examined, alongside the influence of pozzolanic materials, focusing on the chloride migration coefficient and mechanical properties. Six groups of SCC mixtures were created with varying proportions of SF and FA, and different levels of RCA replaced the natural coarse aggregate. The findings reveal a multifaceted impact on SCC behaviour. The chloride migration coefficient exhibits a distinct pattern as the power-on duration increases from 12 to 36 h. Initially, the coefficient increases and then decreases, demonstrating a healing and sealing mechanism within the concrete matrix, which enhances resistance to chloride penetration. The chloride migration coefficient significantly decreased with adding SF and FA. With 15% SF and 30% FA, the coefficient decreased to 59.9% and 49.5%, respectively. Moreover, incorporating RCA in SCC mixtures significantly influences coefficient levels. RCA inclusion at 20% remarkably decreased the coefficient after 12 h by 16.17%. Subsequently, the levels decreased by 39.49% and 46.87% after 24 and 36 h, respectively, compared to the control mixture. This behaviour highlights the importance of RCA in enhancing the resistance of SCC to chloride ingress, a crucial factor for long-term durability. Additionally, mechanical properties such as splitting tensile strength, ultrasonic pulse velocity and surface hardness consistently improved with longer power-on durations and higher RCA and SF content. SCC with RCA and pozzolanic materials exhibits enhanced chloride resistance and superior mechanical performance, making it ideal for sustainable concrete production

Self-compacting concrete produced with recycled concrete aggregate coated by a polymer-based agent: A case study

Understanding the effects of recycled concrete aggregate (RCA) and polymer impregnation on the properties of self-compacting concrete (SCC) is crucial for the construction industry's efforts to reduce environmental impact and utilise recycled materials. This study aims to examine the impact of RCA inclusion and polymer impregnation on the properties of SCC, in response to the urgent demand for sustainable construction practices. Two different methods of polymer impregnation were evaluated to assess their impact on the workability and hardened characteristics of SCC. The SCC mixtures were prepared using river sand (natural fine aggregate (NFA)), natural crushed limestone (natural coarse aggregate (NCA)) and a polymer impregnation level of 0.05 wt% of the water content, with a water-to-cement ratio of 0.34. RCA was used as a complete replacement for NFA and NCA, adhering to the American Society for Testing and Materials (ASTM) C33 standards for recycled fine concrete aggregate (RFCA) and recycled coarse concrete aggregate (RCCA)The workability of the SCC mixtures was evaluated based on the criteria set by the European Federation of National Associations Representing for Concrete (EFNARC). Among the hardened properties, the compressive strength of the hardened properties was tested at four different time intervals (1, 3, 7 and 28 days), and the integrity of the SCC specimens was assessed using ultrasonic pulse velocity. The polymer impregnation process resulted in a slower compressive strength development rate compared to that observed in the control concrete. However, combining polymer impregnation type 1 with either RFCA and NCA or RCCA and NFA significantly increased the 28-day compressive strength by 5.02% and 1.80%, respectively. These findings provide valuable insights into the behaviour of SCC incorporating RCA and polymer impregnation. Optimising the selection and combination of materials can enhance the performance and sustainability of SCC in construction applications

Funktionen und Folgen eines Managementmodells

Kühl S, Sua-Ngam-Iam P. Holacracy. Wiesbaden: Springer Gabler; 2023

Die Hyperformalisierung von Organisationen. Zu den ungewollten Nebenfolgen von Holacracy

Kühl S, Sua-Ngam-Iam P. Die Hyperformalisierung von Organisationen. Zu den ungewollten Nebenfolgen von Holacracy. Zeitschrift Führung + Organisation. 2021;(5):312-314

The Proliferation of Formal Structure: Funktionen und Folgen holakratisch formalisierter Organisation

Dieser Artikel geht der Frage nach, welche Funktionen das Managementkonzept Holacracy für Organisationen erfüllt und welche Folgen sich daraus ergeben. Als empirische Basis dienen dabei Daten, die in fünf holakratischen Organisationen erhoben wurden. Die theoretische Grundlage bildet Luhmanns Konzept der formalen Organisation. Mit der Einführung des Organisationsmodells Holacracy sollen nicht nur Abschottungseffekte durch Abteilungsbildung abgemildert, sondern es soll auch der Filterung von Informationen aufgrund von Hierarchie entgegengewirkt werden. Erkauft wird dies durch eine starke Durchformalisierung der Organisation. Ungewollte Nebenfolgen sind unter anderem das Wuchern der Formalstruktur, die Verunsicherung angesichts der sich schnell ändernden Formalstruktur, die Möglichkeit des Entzugs der Arbeitskraft, die Reduzierung von Initiativen jenseits der Formalstruktur und die Starrheit des Rahmens aufgrund der vorgegebenen holakratischen Organisationsprinzipien.This article examines the functions of the management concept Holacracy and its consequences for implementing organizations. Data collected in five holacratic organizations are used as the empirical basis of this analysis. The theoretical foundation is constituted by Luhmann’s concept of formal organization. The implementation of Holacracy in organizations is supposed to not only weaken isolation effects of division building, but to also counteract the filtering of information caused by hierarchy. This is achieved through a strong formalization of the organization. Unintended side-effects are among others the proliferation of formal structure, the insecurity due to the rapidly changing formal structure, the possibility of work withdrawal enabled through a variety of roles, a reduction of initiatives beyond the formal structure and a rigidity of the organization’s framework due to holacratic principles