Development of 3D Printing Technology for Geopolymers

The article presents the first results of the project under the title: ‘Development of 3D printing technology for construction and facade prefabricated elements made of concrete composites and geopolymers’, grant no. POIR.04.01.04-00-0096/18, funded by the National Centre for Research and Development in Poland, within the framework of programme: ‘Smart Growth Operational Programme 2014-2020, IV Increasing the research potential, 4.1.4: ‘Application projects’. The main aim of the project is design and development of the innovative large-format printer using geopolymers for 3D printing for residential houses. It allows the development of a technology for the production of a universal residential building, with a construction that is easy to transport and fast to assemble, as well as with the possibility of simple and quick expansion depending on the needs of users. The article shows the main idea of the advanced large format 3D printing for geopolymers with using an ergonomic printing method as well as materials research in modern filaments in the form of geopolymers

What Drives Economic Migration Plans? Microdata Analysis for Poland

The aim of the paper is to identify factors influencing economic emigration. The authors use data from socioeconomic surveys (Social Diagnosis 2015 and 2013) with samples of more than 18,000 individuals for the Polish economy. They focus on responses to a question about their potential labor emigration plans, which are seen as a prelude to actual emigration. The outcome of this question was binary; hence a logit model was applied. The results indicate that the key drivers of the propensity to emigrate are registered unemployed status, fluency in at least one foreign language, new skills acquired during the year prior to the survey, and social attitude. On the other hand, older people, women and more educated individuals are less eager to emigrate. The propensity to migrate is also determined by family factors.Artykuł napisano w celu wyznaczenia czynników kształtujących gotowość do emigracji zarobkowej mieszkańców Polski. Posłużono się danymi indywidualnymi pochodzącymi z badania Diagnoza Społeczna 2015 i 2013. Wykorzystano dane z badań, w których respondenci odpowiadali na pytanie o zamiary emigracji zarobkowej, stanowiące ważną przesłankę dla faktycznej emigracji. Udzielone odpowiedzi miały charakter jakościowy (wyrażam chęć/nie wyrażam chęci). Z tego względu narzędziem badawczym był model logitowy, który zapewnia dobre własności statystyczne w przypadku objaśniania zmiennych binarnych. Otrzymane wyniki wskazują, że najważniejszymi czynnikami zwiększającymi prawdopodobieństwo wyrażenia zamiaru emigracji zarobkowej są: formalny status bezrobotnego, znajomość przynajmniej jednego języka obcego, pozyskanie w minionym roku nowych kwalifikacji oraz szeroko rozumiane niezadowolenie (z sytuacji w kraju, miejscu zamieszkania, własnej sytuacji finansowej). Natomiast czynnikami zmniejszającymi to prawdopodobieństwo są: wiek i płeć (osoby starsze i kobiety rzadziej deklarują zamiar emigracji) oraz wysoki poziom formalnego wykształcenia. Ponadto gotowość do emigracji jest także, w sposób istotny, kształtowana przez sytuację rodzinną respondenta

Abrasive water jet machining of fly ash and metakaolin based geo-polymers

In the present study, the abrasive water jet machining (AWJM) of geopolymers prepared from fly ash, metakaolin and sand is discussed. The samples were prepared from sodium promoter, fly ash / metakaolin and sand. The process of activation was made using a 10M sodium hydroxide solution combined with a sodium silicate solution (the ratio of liquid glass - 1:2.5). To produce geopolymers, flakes of technical sodium hydroxide were used and an aqueous solution of sodium silicate (R-145) with a molar module of 2.5 and a density of around 1.45 g/cm3 the tap water. The alkaline solution was prepared by means of pouring the aqueous solution of sodium silicate over the solid sodium hydroxide. The solution was mixed and left until its temperature stablised and the concentrations equalised, which took around 2 hours. The fly ash, sand and alkaline solution were mixed for around 10 minutes using a low-speed mixing machine (in order to obtain a homogeneous paste). The paste was allowed to dry in the shade. The paper investigates the AWJM studies on the prepared geopolymer specimens with varyied input parameters such as standoff distance (1.2 and 3 mm), water pressure (120, 140 and 160 MPa) and feed rate (5, 10 and 15 mm/min). The output parameters such as kerf angle and material removal rate (MRR) were studied with the varying combination of input parameters. From the results, the optimal parameters for machining the geopolymer composites were interpreted

Abrasive water jet machining of fly ash and metakaolin based geo-polymers

In the present study, the abrasive water jet machining (AWJM) of geopolymers prepared from fly ash, metakaolin and sand is discussed. The samples were prepared from sodium promoter, fly ash / metakaolin and sand. The process of activation was made using a 10M sodium hydroxide solution combined with a sodium silicate solution (the ratio of liquid glass - 1:2.5). To produce geopolymers, flakes of technical sodium hydroxide were used and an aqueous solution of sodium silicate (R-145) with a molar module of 2.5 and a density of around 1.45 g/cm3 the tap water. The alkaline solution was prepared by means of pouring the aqueous solution of sodium silicate over the solid sodium hydroxide. The solution was mixed and left until its temperature stablised and the concentrations equalised, which took around 2 hours. The fly ash, sand and alkaline solution were mixed for around 10 minutes using a low-speed mixing machine (in order to obtain a homogeneous paste). The paste was allowed to dry in the shade. The paper investigates the AWJM studies on the prepared geopolymer specimens with varyied input parameters such as standoff distance (1.2 and 3 mm), water pressure (120, 140 and 160 MPa) and feed rate (5, 10 and 15 mm/min). The output parameters such as kerf angle and material removal rate (MRR) were studied with the varying combination of input parameters. From the results, the optimal parameters for machining the geopolymer composites were interpreted

A brief overview of the use of additive manufacturing of con-create materials in construction

Currently, additive technology is becoming increasingly popular in different areas, including its applications in construction industry. The main aim of the chapter is to show the selected applications of 3D printing technology in the construction industry and the usage of this technology on distinct stages of a construction project, from architectural design to performance of residential buildings and other civil engineering constructions. The chapter is based on a critical analysis of the literature sources, as well as the authors' experiences. The data collected are supported by selected case studies from five projects. The main findings show that 3D printing brings a lot of advantages in the construction industry, for instance: low labour costs, less waste, and high efficiency, but it still requires development and optimization

Additive Manufacturing in Underwater Applications

Additive manufacturing (AM), commonly named 3D printing, is a promising technology for many applications. It is the most viable option for widespread use in automated construction processes, especially for harsh environments such as underwater. Some contemporary applications of this technology have been tested in underwater environments, but there are still a number of problems to be solved. This study focuses on the current development of 3D printing technology for underwater applications, including the required improvements in the technology itself, as well as new materials. Information about underwater applications involving part fabrication via AM is also provided. The article is based on a literature review that is supplemented by case studies of practical applications. The main findings show that the usage of additive manufacturing in underwater applications can bring a number of advantages—for instance, increasing work safety, limiting the environmental burden, and high efficiency. Currently, only a few prototype applications for this technology have been developed. However, underwater additive manufacturing is a promising tool to develop new, effective applications on a larger scale. The technology itself, as well as the materials used, still require development and optimization

Mechanical Properties of Short Fiber-Reinforced Geopolymers Made by Casted and 3D Printing Methods: A Comparative Study

The main objective of this article is to develop ceramic-based materials for additive layer manufacturing (3D printing technology) that are suitable for civil engineering applications. This article is focused on fly ash-based fiber-reinforced geopolymer composites. It is based on experimental research, especially research comparing mechanical properties, such as compressive and flexural strength for designed compositions. The comparison includes various composites (short fiber-reinforced geopolymers and plain samples), different times of curing (investigation after 7 and 28 days), and two technologies of manufacturing (casted and injected samples—simulations of the 3D printing process). The geopolymer matrix is based on class F fly ash. The reinforcements were green tow flax and carbon fibers. The achieved results show that the mechanical properties of the new composites made by injection methods (simulations of 3D technology) are comparable with those of the traditional casting process. This article also discusses the influence of fiber on the mechanical properties of the composites. It shows that the addition of short fibers could have a similar influence on both of the technologies