Protecting the built cultural heritage is one of the most important tasks in architectural practice. The process of repair is time-consuming, weather-dependent, and sensitive to materials applied. Introducing new materials in historic building repair in order to decrease the time needed for repair, brings some risk in the preservation process. The most common material for masonry repair is lime mortar. Adding cement to lime mortar can improve the mechanical properties of mortar and speed up the repair process. The high amount of cement may increase the strength, but decrease ductility and permeability of mortar, causing damages to protected buildings. An increase in strength with the smallest amounts of cement demands optimization of water content in the mixture. Tests were performed to investigate the influence of the water/binder (w/b = water/(lime + cement) ratio on mortar strength and water permeability. An air-entraining agent (AEG) was introduced to improve permeability. Results confirmed that adding small amounts of cement to lime (20% by weight) and decreasing of w/b ratio, improves the strength, with almost negligible influence on water permeability. The addition of very small amounts of AEG did not decrease the strength, nor the permeability.

The subject of this paper is the elements of a timber lamella structure: the lamellae and their joints. The lamella structure is usually in a diamond pattern, so it relies on additional elements to achieve stability. The analysis of the elements precedes the design of a prototype of a timber lamella vault. The characteristic diamond pattern can be kept for the design of rigid or semi-rigid joints. The design of the joints is challenging, so this paper focused on the analysis and systematization of joints designed for timber lamella structures. The existing timber lamella joints were classified and analyzed based on five parameters: eccentricity, load capacity, the number of elements, easiness of assembly, and adaptability to the circular cylindrical surface, to systemize the existing joints and propose a new one. A design for a new joint was proposed based on the presented joints. The systematization and discussion gave a comparison of all joints, their advantages, and limitations. The conclusion was that the geometry of a circular cylinder and the type of elements for the prototype confirmed all the benefits of the historical lamella structures: uniformity of elements, easy assembly, and economical design.

This paper presents an experimental study on the behavior of the bond between cotton knitted textile cut-offs and a polymer–cement binder. The first part of the research examined the influence of polymer–cement coating on the maximum tensile load of this type of textile. For this purpose, the maximum tensile force of plain textiles and polymer–cement-coated textiles, with one and two layers of textiles, was tested. The results showed that polymer–cement coating increases the maximum tensile force by an average of 36%, and double polymer–cement coating by an average of 79% compared to twice the maximum force of the textile itself. The second part of the research examined the influence of the overlap length of independent textile parts on the transfer of tensile force from one part to another. Three overlap lengths were tested: 25 mm, 38 mm and 50 mm. The results indicate the conclusion that it is possible to make a continuous polymer–cement–textile surface from knitted textile parts, and suggest that for this type of textile, an overlap length greater than 25 mm is sufficient to transfer the same order of magnitude of maximum tensile forces as for continuous textiles. Additional research is needed to more precisely determine the sufficient overlap length. This research confirmed the hypothesis that cotton knitted textile waste cut-offs could be effectively bonded with a polymer–cement binder to enable the transfer of tensile forces and used as a material for the manufacture of textile formwork.

Fashion and textile industry generate substantial volume of waste, during the production phase, as well as in the consumer phase. Textile waste is disposed in the landfills or incinerated, significantly affecting the environment. At the same time, construction industry faces demand to consider different approaches to the conventional formwork systems, which are resource intensive and disposed after the use. Feasibility of the usage of the cut-off knitted textile waste bonded with polymer-cement binder to create the composite formwork for casting concrete and mortar elements is presented in this paper. Experiments are designed with different types of cement-based mixtures to make the textile formwork composite and the polymer-cement mixture. Experimental research tested the bond between two pieces of textile bound by the selected polymer-cement binder and a proposal was given for determining the required overlap length. Obtained testing results for adequate and optimal samples, showed that the recycled textile waste may be used as efficient and low-cost alternative to traditional formwork, while providing flexible and non-prismatic geometrical shapes of the products and reducing the environmental impact.