Modern Methods of Experimental and Computational Investigations in Area of Construction

文章题目 页数

作者: Lukáš Hlubocký, Jaromír Hrůza, Lukas Novák, Jaroslav Topič
摘要: This paper deals with using resonance method for determine a development of mechanical properties of gypsum matrix reinforced with steel fibers from recycled tires. Mechanical properties which were monitored are the dynamic Young's modulus and dynamic shear modulus. Both properties were measured by a resonance method on samples 28 days old. The aim was to check the possibilities of using the recycled tires in construction as reinforcement to the gypsum binder. Many published papers deals with composite materials based on gypsum, but mainly with standard non-metallic reinforcement such as glass fibers, PP and PE fibers etc.
作者: Ondřej Holčapek, Filip Vogel
摘要: This paper deals with advanced application of textile reinforced concrete for strengthening and stabilization of existing load-bearing structure elements. Slim layer of fine grain concrete with compressive strength over 100 MPa was applied on one year old concrete beams with dimension 100 x 100 x 400 mm. Different number of layers of two types of textile fabrics was applied into concrete layer. One textile fabric was made from alkali-resistant glass fabric with surface density 585 g/m2 and the second was made from basalt fabric with surface density 260 g/m2. One layer of basalt textile fabric (surface density 120 g/m2) was applied on the top of strengthening layer to prevent shrinkage cracks of high strength cement matrix. Evaluation of destructive four points bending test of strengthened and reference specimens provided the efficiency of performed strengthening solution. Continual load and deflection measurement during bending test enables to create load-deflection diagram, where the action of textile can be observed.
作者: Jaromír Hrůza, Jaroslav Topič, Lukáš Hlubocký, Tomáš Plachý
摘要: This article deals with the usage of recycled concrete, which arises from demolitions of concrete structures. The aim is to find out what amount of recycled concrete as a binder influences final mechanical properties of the concrete. It was found that the gradual replacement of cement with recycled concrete causes reduction of the dynamic Young’s modulus and decreases the size of the increase in strength during the first 28 days. Overall, it is confirmed that recycled concrete may be used for concrete structures with regard to their purpose, importance and applicability.
作者: Miloš Huttner, Petr Fajman
摘要: This paper is focused on carrying capacity testing of five different types of membrane connections. Three reference samples for each type of connection were tested for tensile strength. Low measured peak force value and especially the way breakage outside of the join indicative of a wrong material, and not on the connection. The obtained values were compared with technical datasheet of the material manufacturer, which has been non-compliance. It confirms the assumption that the material was changed, which could harm to the user.
作者: Mirek Jarolím, Andrej Osvald, Václav Nežerka, Jaroslav Topič, Richard Ťoupek, Jakub Antoš, Pavel Tesárek
摘要: Values of the dynamic Young’s modulus were monitored on cement-based samples containing recycled concrete. In particular, the study was focused on investigation of the relationship between the elastic stiffness and amount of recycled microfiller to replace Portland cement. The amount of the microfiller was ranging between 30 and 70 % per weight of the samples. The samples were cured in common laboratory conditions for 50 days, followed by their placement into a water bath for 2 days and consequent natural drying period for 6 days. The development of elastic stiffness was monitored using non-destructive impulse excitation method in order to demonstrate the influence of hydration when the specimens are stored in high humidity. The increase of elastic stiffness proves a secondary hydration of both – Portland cement and cement grains from the recycled cementitious material.
作者: Pavel Klapálek, Lenka Melzerová
摘要: This article is focused on GLULAM (glued laminated timber) beams and determination of their properties by using non-destructive method. This text is mainly focused just on part of more complex research of glued laminated timber beams. This text is focused on non-destructive method, which is the method of spike that uses device called Pilodyn 6J for measurement. Results of this method are in form of Young ́s modulus of elasticity. This article will describe how the method of spike works, with basic description, describes the tested material and compare the results of testing. In the conclusion we discuss the results, make conclusions and describe the way of our further research of glued laminated timber beams.
作者: Aneta Maroušková
摘要: A numerical analysis for masonry columns is presented in this paper. The behavior and character of deformation of compressed unreinforced masonry columns is investigated and compared with the deformation of masonry columns reinforced by FRP wrapping. The experimental program is part of a research project NAKI [1]. Both, the bricks and the mortar are modeled as 3D continuum and to the interface between these two materials a non-linear contact law is assigned. The contact between reinforcement and masonry support is considered as perfectly-adherent. Two different cases are simulated - the ratio of Young ́s modulus of brick and Young’s modulus of mortar is 5:1, respectively 1:5. For all simulations the commercial software package ABAQUS was used and the obtained numerical results are discussed.
作者: Ivana Žabičková, Tereza Otcovská, Pavel Padevět
摘要: Clay is a traditional construction material which has got to background with introduction of modern materials to building practice. Nowadays, there are two main reasons for unfired clay materials interest grow. First, a clay masonry is in an agreement with sustainable development principles. Second, the unburned clay constructions have positive influence on a human health. However, there is not proper material available for clay constructions design due to lack of proper examination of its mechanical properties. This submission concerns with compressive strength of low walls made of unburned clay.
作者: Barbora Mužíková
摘要: The best way how to test fracture mode II and determinate the critical factor KII of cement paste beams is investigated. Several methods are presented and the test based on a theory of the double-edge notched infinite plate is described in detail and will be carry out.