Use of high performance concrete with reinforcement made of technical textile is increasing and new applications are being found. This paper presents new technology for the lightening of the panels made of textile reinforced concrete, which is being developed. The main focus of this research is to produce concrete elements suitable for use as facade panels with the least possible weight and environmental impact. Mechanical characteristics were measured on testing specimens with thickness of 18 mm with lightening representing 47% of their volume. Minimum thickness of concrete was 4 mm and therefore the reinforcement was covered by approximately 1.5 mm of concrete matrix. The strength of experimental test panels was measured in four-point bending stress test. Due to one-sided lightening and asymmetrical cross-section therefore, the tests were performed in both directions. For better interpretation of the results were the specimens of lightened panels tested alongside non-lightened specimens with the same thickness. Based on measured values, maximal dimensions of lightened facade panels were designed.

High performance concrete reinforced by technical textiles has found a wide range of applications in recent years. One of the most widespread is the use of this composite for the very thin facade panels of various shapes and technical solutions. This paper presents an unique way how to lighten the facade panels made of high performance concrete (HPC) reinforced by technical textiles, which are additionally equipped with LEDs, so that a sufficient distance can be watch programmed based image displays.

The development of light and very thin concrete building structures and demand for extremely thin elements in design are inter alia reasons for the development of composite materials as non-traditional reinforcement. Composite materials are currently used as reinforcement mostly in the form of fiber reinforced polymer bars similar to traditional steel reinforcement bars, but the last decade sees also rise in the use of technical textiles. This article is focused on the interaction between impregnated textile reinforcement and high-performance concrete matrix and its easy determination using originally modified pullout test. The second aim of this article is improvement of interaction conditions between reinforcement and cementitious matrix using fine-grained silica sand applied on the surface of the composite reinforcement similarly to the traditional fiber reinforced polymer reinforcement with commonly used diameters. To investigate an effect of this modification a bending test was performed on small thin concrete slabs with different amounts of reinforcement.

The use of recycled masonry aggregate for concrete is mostly limited by the worse properties in comparison with natural aggregate. For these reasons it is necessary to find ways to improve the quality of recycled masonry aggregate concrete and make it more durable. One possibility is utilization of crystalline admixture which was verified in this study by laboratory measurements of key material properties and durability. The positive influence of mineral admixture was proved for freeze-thaw resistance. The positive impact to carbonation resistance was not unambiguous. In conclusion, the laboratory evaluation shows how to improve the durability of recycled masonry aggregate concrete, however, it is necessary to investigate more about this topic.

This paper presents a model of small experimental facade panel using four-point bending test. The facade panel with dimensions 100 x 360 mm and thickness approximately 18 mm was slightly reinforced using two layers of impregnated technical fabric from AR-glass roving. The amount of reinforcement in cross-sectional area of the concrete element is small and it is a reason of plastic joints initiation under the loading supports. The purpose of this experiment was validation of all used material parameters from the previous research in the program for nonlinear analysis of concrete and reinforced concrete Atena Engineering. For slightly reinforced concrete elements are monitored parameters better visible especially interaction between reinforcement and used concrete. The load transfer to the concrete element from the testing machine is typically modeled using some small steel plate. This paper shows the difference in results if we insert another flexible plate between the steel plate and the concrete element with a small defined stiffness.

High‐performance concrete (HPC) is a cement‐based material with excellent properties and durability which determines high‐level structural utilization. However, the necessity of high‐quality natural resources such as quartz powder and sand and a high amount of cement and silica fume and reinforcement by fibers causes a high environmental footprint and costs. One of the possible ways to reduce the environmental footprint and cost of the HPC/UHPC is to replace the powder or sand with secondary raw materials. In this study, the two types and three fractions of fine recycled concrete aggregate (fRCA) are used as supplementary materials in HPC. The reference mixture is based on the UHPC mixture without reinforcement to find out the influence of aggregate replacement. The properties of fresh and hardened concrete are examined. The results show a slight decline of mechanical properties however the autogenous shrinkage decrease with the replacement of natural aggregate by fRCA, which shows the possibilities of natural resources savings and thus leads to a lower environmental footprint of concrete structures as a contribution to the solution of sustainable development goals set by the United Nations in 2015 as an action plan up to 2030.

Textile-reinforced concrete (TRC) is a material consisting of high-performance concrete (HPC) and tensile reinforcement comprised of carbon roving with epoxy resin matrix. However, the problem of low epoxy resin resistance at higher temperatures persists. In this work, an alternative to the epoxy resin matrix, a non-combustible cement suspension (cement milk) which has proven stability at elevated temperatures, was evaluated. In the first part of the work, microscopic research was carried out to determine the distribution of particle sizes in the cement suspension. Subsequently, five series of plate samples differing in the type of cement and the method of textile reinforcement saturation were designed and prepared. Mechanical experiments (four-point bending tests) were carried out to verify the properties of each sample type. It was found that the highest efficiency of carbon roving saturation was achieved by using finer ground cement (CEM 52.5) and the pressure saturation method. Moreover, this solution also exhibited the best results in the four-point bending test. Finally, the use of CEM 52.5 in the cement matrix appears to be a feasible variant for TRC constructions that could overcome problems with its low temperature resistance.

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