The article presents a concept of a lunar base that would take advantage of the natural shape of an egg. Several versions of egg-shaped habitat structures characterized by different sizes are presented. Possible locations of habitats both on lunar surface and in craters were discussed. Advantages and disadvantages of particular locations were also pointed out. The proposed in the paper concept of an egg-shaped structure is characterised by a spatial character based on Voronoi diagram and would be implemented using a 3D-printed method. The presented 3D-printed structure was designed to be light and suitable to be covered by lunar soil. As a necessity in the developed concept, in situ resources utilization was addressed in order to generate products using local sources to reduce the number of materials that would be required to be transported from Earth. At the end of the paper, future areas of research and tests are highlighted.

With the recent and rapid development of concrete technologies and the ever-increasing use of concrete, adapting concrete to the specific needs and applications of civil engineering is necessary. Due to economic considerations and care for the natural environment, improving the methods currently used in concrete design is also necessary. In this study, the author used principal component analysis as a statistical tool in the concrete mix design process. Using a combination of PCA variables and 2D and 3D factors has made it possible to refine concrete recipes. Thirty-eight concrete mixes of different aggregate grades were analyzed using this method. The applied statistical analysis showed many interesting relationships between the properties of concrete and the content of its components such as the clustering of certain properties, showing dependence between the properties and the quantities of certain ingredients in concrete, and reducing noise in the data, which most importantly simplifies interpretation. This method of analysis can be used as an aid for concrete mix design.

In this paper, the authors made an attempt to detect the fibre content and fibre spacing in a steel fibre reinforced concrete (SFRC) industrial floor. Two non-destructive testing (NDT) methods, an electromagnetic induction technique and a radar-based technique, were applied. The first method allowed us to detect the spacing in subsequent layers located in the thickness of the slab. The result of the second method was a 3D visualization of the detected fibre in the volume of concrete slab. The conducted tests showed aptitude and limitations of the applied methods in estimating fibre volume and spacing. The two techniques also allowed us to locate the areas with relatively low fibre concentration, which are very likely to be characterized by low mechanical properties.

The presented research program is focused on the design of a structural lightweight fiber-reinforced concrete harnessing an internal curing process. Pre-soaked waste red ceramic fine aggregate and pre-soaked artificial clay expanded coarse aggregate were utilized for the creation of the mix. Copper-coated steel fiber was added to the mix by volume in amounts of 0.0%, 0.5%, 1.0%, and 1.5%. Test specimens in forms of cubes, cylinders, and beams were tested to specify the concrete characteristics. Such properties as consistency, compressive strength, splitting tensile strength, static and dynamic modulus of elasticity, flexural characteristics, and shear strength were of special interest. The achieved concrete can be classified as LC12/13. A strength class, according to fib Model Code, was also assigned to the concretes in question. The proposed method of preparation of concrete mix using only pre-soaked aggregate (with no extra water) proved to be feasible.

This research was inspired by the growing global shortage of natural aggregates. Different types of waste ceramics (apart from recycled concrete) are the most popular materials for the production of waste aggregates as possible substitutes for natural ones. The aim of this research was to analyse the efficiency of different aggregate mixes composed of waste and natural materials focusing on two waste ceramic aggregates, which were prepared concrete mixes based on specifically composed aggregates (blend of natural aggregate, porous and iron oxide-rich (red) waste ceramic aggregate, and dense, kaolin-based (white) waste ceramic aggregate). All aggregates were thoroughly tested before utilisation for concrete mix creation. Altogether, four blends of aggregates were prepared in order to prepare concrete mixes using a simplex experiment design. The mixes were then modified by adding various amounts of crimped steel fibre. Such properties of hardened steel fibre-reinforced concrete (SFRC) such as density, compressive strength, shear strength, ultrasound propagation velocity, dynamic modulus of elasticity, and limit of proportionality during flexural testing were of special interest. Tests were conducted according to European and Japanese standards. The achieved fibre-reinforced concretes were characterised by satisfactory strength characteristics, thereby enabling the substitution of traditional reinforcement. Strength classes according to the fib Model Code 2010 were assigned.