Yes / This paper investigated the bond characteristics between eight types of nanofillers modified reactive powder concrete (RPC) and plain steel bars, aiming to explore the modifying mechanisms and establish a bond-slip relationship model for nanofillers modified RPC and steel bar interface. The experimental results indicated that the incorporation of nanofillers can increase the bond strength and reduce the slip between RPC and plain steel bars. It was shown that a 2.15 MPa/20.5% of absolute/relative increase in cracking bond strength, a 1.25 MPa/10.3% of absolute/relative increase in ultimate bond strength, a 2.35 MPa/22.4% of absolute/relative increase in residual bond strength, a 0.592 mm/56.5% of absolute/relative reduction in ultimate bond slip, and a 1.779 mm/52.1% of absolute/relative reduction in residual bond slip were the best achieved due to the addition of various nanofillers. The enhancement of nanofillers on RPC-steel bar interface has been mainly attributed to RPC microstructure improvement, optimization of intrinsic compositions, and elimination of defects in the interface, especially the underside near steel bar, due to the nano-core effect of nanofillers enriched in the interface. In addition, the bond-slip relationship of nanofillers modified RPC-steel bar interface can be accurately described by the proposed model considering an initial branch. / The authors would like to thank the funding offered by the National Science Foundation of China (51978127 and 51908103), and the Fundamental Research Funds for the Central Universities (DUT21RC(3)039).

This diploma thesis deals with the position of diagnostics of reinforced concrete structures in the building industry. The theoretical part deals with the research of methods for practical part of this thesis and basic imagine of procedure. The practical part deals with the survey of an existing building, quality of concrete and reinforcement of elements. The last part is the static calculation of the selected element for the intended use of the building. At the end, the results of the construction and technical survey are evaluated.

Die Partikelinteraktionen in Suspensionen führen zu charakteristischen Phänomenen wie Partikel-agglomeration und Segregation. In dieser Arbeit werden Beiträge zu diesen Vorgängen am Beispiel einer Stahlschmelze und in Pumpbeton untersucht. Es wurden Agglomerationsmodelle für die Kollision kugelförmiger und nichtkugelförmiger nichtmetallischer Einschlüsse in Stahl entwickelt. Diese zeigen eine erhöhte Kollisionsrate für Partikelcluster und den Einfluss der Lubrikationskräfte für größere Partikel, die der Agglomeration entgegen wirken. Für kleinere Partikel dominieren Van der Waals Kräfte. In dichten Suspensionen wie Beton sind Segregationseffekte wie die Ausbildung einer Gleitschicht an der Rohrwand relevant. Es wurden zwei Mechanismen identifiziert und beschrieben, die zur Segregation in einem Modellbeton führen und der Einfluss auf den Pumpdruck wurde betrachtet. DEM Simulationen des Pumpprozesses zeigen die starke Neigung zur Segregation für Partikel mit hoher Reibung und den Viskositätseinfluss der Fluidmatrix. Zusätzlich wird ein DEM-Modell für deformierbare Partikel vorgestellt und mit experimentellen Daten verglichen.

Various anchorage systems including both cast-in-place and post-installed anchors have been developed for fastening both non-structural and structural components to concrete structures. The need for increased flexibility in the design of new structures and strengthening of existing concrete structures has led to increased use of various metallic anchors in practice. Although millions of fasteners are used each year in the construction industry around the world, knowledge of the fastening technology remains poor. In a sustainable society, buildings and structures must, from time to time, be adjusted to meet new demands. Loads on structures must, in general, be increased to comply with new demands, and the structural components and the structural connections must also be upgraded. From the structural connection point of view, the adequacy of the current fastenings for the intended increased load must be determined, and inadequate fastenings must either be replaced or upgraded. The current design models are generally believed to be conservative, although the extent of this behavior is not very clear. To address these issues, the current models must be refined to allow the design of new fastenings and also the assessment of current anchorage systems in practice. The research presented in this thesis consists of numerical and experimental studies of the load-carrying capacity of anchors in concrete structures. Two different types of anchors were studied: (I) cast-in-place headed anchors, and (II) post-installed adhesive anchors. This research focused particularly on the tensile load-carrying capacity of cast-in-place headed anchors and also on the sustained tension loading performance of post-installed adhesive anchors. The overall objective of this research was to provide knowledge for the development of improved methods of designing new fastening systems and assessing the current anchorage systems in practice. For the cast-in-place headed anchors (I), the influence of various parameters including the size of anchor head, thickness of concrete member, amount of orthogonal surface reinforcement, presence of concrete cracks, concrete compressive strength, and addition of steel fibers to concrete were studied. Among these parameters, the influence of the anchor head size, member thickness, surface reinforcement, and cracked concrete was initially evaluated via numerical analysis of headed anchors at various embedment depths. Although these parameters have considerable influence on the anchorage capacity and performance, this influence is not explicitly considered by the current design models. The numerical results showed that the tensile breakout capacity of headed anchors increases with increasing member thickness and/or increasing size of the anchor head or the use of orthogonal surface reinforcement. However, their capacity decreased considerably in cracked concrete. Based on the numerical results, the current theoretical model for the tensile breakout capacity of headed anchors was extended by incorporating several modification factors that take the influence of the investigated parameters into account. In addition, a supplementary experimental study was performed to verify the numerically obtained findings and the proposed refined model. The experimental results corresponded closely to the numerical results, both in terms of failure load and failure pattern, thereby confirming the validity of the proposed model. The validity of the model was further confirmed through experimental results reported in the literature. Additional experiments were performed to determine the influence of the concrete compressive strength and the addition of steel fiber to concrete on the anchorage capacity and performance. These experiments showed that the anchorage capacity and stiffness increase considerably with increasing concrete compressive strength, but the ductility of the anchor decreases. However, the anchorage capacity and ductility increased significantly with the addition of steel fibers to the concrete mixture. The test results also revealed that the tensile breakout capacity of headed anchors in steel fiber-reinforced concrete is significantly underestimated by the current design model. The long-term performance and creep behavior of the post-installed headed anchors (II) was evaluated from the results of long-time tests on adhesive anchors under sustained loads. In this experimental study, adhesive anchors of various sizes were subjected to various sustained load levels for up to 28 years. The anchors were also exposed to several in-service conditions including indoor temperature, variations in the outdoor temperature and humidity, wetness (i.e., water on the surface of concrete), and the presence of salt (setting accelerant) additives in the concrete. Among the tested in-service conditions, variations in the outdoor temperature and humidity had the most adverse effect on the long-term sustained loading performance of the anchors. Based on the test results, recommendations were proposed for maximum sustained load levels under various conditions. The anchors tested under indoor conditions could carry sustained loads of up to 47% of their mean ultimate short-term capacities. However, compared with these anchors, the anchors tested under outdoor conditions exhibited larger creep deformation and failure occurred at sustained loads higher than 23% of their mean ultimate short-term capacities. Salt additives in concrete and wet conditions had negligible influence on the long-term performance of the anchors, although the wet condition resulted in progressive corrosion of the steel. Based on the experimental results, the suitability of the current testing and approval provisions for qualifying adhesive anchors subjected to long-term sustained tensile loads was evaluated. The evaluations revealed that the current approval provisions are not necessarily reliable for qualifying adhesive anchors for long-term sustained loading applications. Recommendations were given for modifying the current provisions to ensure safe long-term performance of adhesive anchors under sustained loads.

This master thesis focused on the design and elaboration of project documentation for the purpose of a storage area with an administrative building, consisting of the premises SO 01 - storage hall and SO 02 - administrative building. Objects are located on parcels no. 4006/16, 4006/17, 4006/18, 4006/19, 4006/23, 4006/24, 4006/26, 4006/27, 4006/28, 4006/29, 4006/30, 4006/31, 4006/32, in the cadastre unit Dolní Bojanovice. They are located on an investor's land. Traffic connection is provided by the exit from the car park on the local road. All engineering infrastructure engineering networks are located near the site. The design of the building respects the local zoning plan. Project documentation is prepared in accordance with the current wording of applicable laws, decrees and standards. The project solves the structure functionally divided into objects SO 01 and SO 02, which are both operationally and structurally connected. The construction of objects is statically independent. The object SO 01 is designed for the storage of building material intended for storage in dry rooms. In addition to the storage space there is the air-conditioning machine room. The SO 02 facility serves administrative and staffing facilities. In the basement of the building there are rooms of technical background and archives. The SO 01 is designed as a full-metal mounted object with a counter roof and foundation pads. The design system of the SO 01 object is columnar with steel columns. The SO 02 building is designed from a wall construction system made of aerated concrete blocks with reinforced concrete ceilings, base strips and a flat roof. The SO 01 has a 65.5x20.2 m ground plan. The perimeter shell of the building consists of assembled sandwich panels with a core of pure material. The largest ground plan dimensions of the so 02 are 26.75x10.35 m. The perimeter shell is made up of 375 mm piece concrete blocks with a 150 mm contact system.

Possibilities of modeling non-linear behavior of concrete within standard room temperatures and increased fire-load values using FEM software ANSYS are studied. Temperature dependences of material models are considered. Fire resistance of reinforced concrete and concrete-steel composite construction is analyzed. Fire loads are defined in accordance with relevant standards. Non-linear structural transient analyses are calculated after temperatures were determined by transient thermal analyses. Results obtained from analyses of simple reinforced concrete structure are compared with approach of isotherm 500 °C method.

The subject of this diploma thesis is the design and assessment of main load-bearing elements od the steel structure of shopping gallery in Hodonín. Part of floor plan is rectangular and rest of it is half-circled. Object's dimensions are 7é m x 147,75 m (and roof overhang 1,5 m on each side), the height of the ridge is 13,43 m and the height of the roof's dome is 22,70 m. It's a two-storey building. The load-bearing structure consist of pin-suported columns, in this case there is max. 8,5 m distance between them in direction of main frame. The distance between main frames is 9 m. The spatial rigidity of the structure is ensured with floor slabs and system of bracings. The cladding consists of sandwich panels, roof's fanlights and dome of glazed areas. Most of elements are made of S355 steel.

This final thesis is divided into two parts. The first, theoretic part is focused on issue about industrial concrete floors, their production and adjustment. Special attention is paid to the mineral shakes, steel fibres and concrete, which is used to these constructions. There are more information about specific standardized tests of steel fibre concrete and some damages of concrete floors in other chapters. Second part of the diploma thesis is practical. Theoretical knowledge are applied to the actual construction. Survey methodology and diagnostic work are also desribed. Data processing and evaluation with the commentary is also attached to this part. The conclusion summarizes the results and selected findings relating to the issue are also included there.