Advanced Materials Research Vol. 1054

Abstract: Fibre-reinforced composite materials are becoming important in many areas of technological application. In addition to the static load, such structures may be stressed with short-term dynamic loads or even dynamic impact loads during their lifespan. Impact loading of construction components produces a complex process, where both the characteristics of the design itself and the material parameters influence the resultant behavior. It is clear that reinforced concrete with fibers has a positive impact on increasing of the resistance to impact loads. Results of two different impact load tests carried out on drop-weight test machine are presented in this report.

Abstract: The paper summarizes results of pilot fatigue testing of concrete slabs resting on granular base in testing box. The project aimed at verification of recent findings that fatigue resistance of concrete slabs is much higher than that predicted by using concrete fatigue characteristics from beam testing. Paper presents additional testing results that confirm enhanced fatigue resistance of concrete slabs. Further research is envisioned to supplement pilot testing results and to receive new results also on fatigue resistance under concrete recycling scheme.

Abstract: The goal of presented research is an assessment of fundamental mechanical properties and resistance to water ingress of concrete with non-cyclic alkanes. Compressive and tensile strength, water absorption capacity and sorptivity of concrete made with and without an admixture of non-cyclic alkanes has been analysed. The paraffin enriched concretes have been made with 1% (C1F and C1C) and 3% (C3F and C3C) volume addition of paraffin wax. The paraffin wax has been used in two grades of comminution: fine (FP) in CxF concretes and coarse (CP) in CxC concretes. A significant (35%) loss of compressive strength of concretes with admixtures has been noticed and no loss in tensile strength was observed. Up to 25% of water absorption capacity reduction and irrefutable (8 times) sorptivity reduction has been also noticed, but only in the case of concrete made with admixture of FP.

Abstract: Asphalt mixtures are less resistant to static load in comparison with a cement-concrete pavements. At traffic ways in logistic areas, weighted intersections, bus stops or climbing lanes can occur typical fault in the form of bruises, cross roller blinds or rut. This article deal with asphalt composites, which are known as materials, technologies, structural formations that can minimize this condition. In individual cases it is possible to use solid type VMT mix asphalt (mixture of high stiffness modulus), the technology of asphalt mixtures with fiber reinforcement, modification by natural asphalt binders, the use of polymer modified by binders or technology asphalt and cement concrete (ACC). Using ACC is despite the higher investment costs of these technology in specific cases preferable because of the less frequency and duration of repairs.

Abstract: Paper is focused on the determination of sorption properties of mortars modified by sealing admixture. Ability of building materials to transport water has an important influence to other properties, predominantly durability. Realized experimental program introduces results of long-term measurements of transport properties presented by capillary absorbability.

Abstract: The paper presents results of experimental works focused on property verification of concretes with an admixture of polypropylene fibres with various surface treatments. Common production polypropylene fibres with surface lubrication, polypropylene fibres without surface treatment and low temperature plasma treated polypropylene fibres were used for the testing.

Abstract: This paper is aimed at a comparison of different types of steel fibres in relation to their influence on the final mechanical properties of High Strength Concrete (HSC). The most affected characteristics of concrete were fracture energy, flexural and split strength, which are the main goal of using fibre reinforcement, as HSC has otherwise low ductility, that can result in sudden failure of a concrete structural element. Expected better behaviour of high-strength steel fibres hooked at the ends than of the ones of normal strength with only flattened ends was approved. The highest values of fracture energy was achieved with the longest steel fibres – 60 mm (diameter 0.75 mm). Whereas shorter fibres (30 mm) of the same diameter reached increased flexural and split strength.

Abstract: Application of cellulose fibers in cement composites is one of the possibilities for achieving better utility properties of these composites. This article presents findings of experimental works concerned on increasing the resistance of cement composites to high temperatures. Properties of cement composites with the addition of cellulose fibers Greencel were observed. Rheological properties of fresh composite, mechanical properties and changes of properties after heat load were evaluated. The best mechanical properties showed the samples with technical cellulose, namely with the fiber G-55T and G-700T. The process of cellulose fiber degradation at high temperatures was documented. The process of carbonization of cellulose fibers leads to the creation of pore system, which enables to increase the resistance of cement composites to high temperatures.

Abstract: This article deals with influence of the ground granulated blast furnace slag (GGBS) in the mixture of high performance concrete. It is a powder active addition used in concrete which is characterized certain cementitious properties. Influence of this addition was experimentally verified. In the first series, partial replacement of cement by GGBS was tested. In the second series, GGBS was added to the original reference mixture. Studied parameters were compressive strength, tensile strength and workability. The tests have shown that a partial replacement of the cement by GGBS is possible for achieving the desired workability or if we need to reduce the price of concrete.

Abstract: Outstanding features of UHPC - Ultra High Performance Concrete are generally known. It has become increasingly used worldwide. For a better understanding of the material some features like the bond of reinforcement and UHPC has to be quantified. Research is focused on determination the bond stress between two types of the reinforcement (prestressing strands and bars) and different types of UHPC. Main goal of the research is to show significant increase in the shear stress in bond of UHPC compared to ordinary concrete. For evaluation of the bond stress the pull-out test were carried out. Specimens were prepared according to standard and tested in the laboratory. The influence of different material properties and different anchorage length of reinforcement to bond behaviour was examined.