Bond Characteristics of TRC Slabs Cured in Autoclave

2016 ◽  
Vol 722 ◽  
pp. 305-310 ◽  
Author(s):  
Ondřej Holčapek
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
Bending Test ◽  
Cement Matrix ◽  
Textile Reinforced Concrete ◽  
Aesthetic Quality ◽  
Production Program ◽  
Curing Conditions ◽  
Real Practice ◽  
Bond Characteristics

Textile reinforced concrete (TRC) found its application in real practice and several producers and companies included TRC ́s elements into their production program. The most popular and widespread are slim façade panels with high aesthetic quality and excellent durability. Curing conditions influence the final properties, which is important especially in precast production where special devices can be used. This paper deals with experimental investigation of bond characteristics of slabs made from TRC hydrothermally cured in autoclave device and reference slabs cured in laboratory conditions for 28 days. Dimension of TRC slabs was 230 x 100 x 20 mm. Compressive strength 100 MPa characterizes used cement matrix (laboratory cured after 28 days). Basalt and AR-glass fabrics with different properties were used as reinforcement. Three-points bending test with clear span of supports 200 mm evaluated maximum bond capacity and load-deflection diagrams described character of failure and ductility.

scholarly journals ANALYSIS OF MECHANICAL PROPERTIES OF HYDROTHERMALLY CURED HIGH STRENGTH CEMENT MATRIX FOR TEXTILE REINFORCED CONCRETE

2015 ◽  
Vol 55 (5) ◽  
pp. 313 ◽  
Author(s):  
Ondřej Holčapek ◽  
Filip Vogel ◽  
Petr Konvalinka
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
High Strength ◽  
Positive Influence ◽  
Cement Matrix ◽  
Textile Reinforced Concrete ◽  
Curing Conditions ◽  
Hydrothermal Curing ◽  
Concrete Production

The main objective of this article is to describe the influence of hydrothermal curing conditions in an autoclave device (different pressure and temperature), which took place at various ages of a fresh mixture (cement matrix – CM, and fibre-reinforced cement matrix – FRCM), on textile reinforced concrete production. The positive influence of autoclaving has been evaluated through the results of physical and mechanical testing – compressive strength, flexural strength, bulk density and dynamic modulus of elasticity, which have been measured on specimens with the following dimensions: 40×40×160mm<sup>3</sup>. In addition, it has been found that increasing the pressure and temperature resulted in higher values of measured characteristics. The results indicate that the most suitable surrounding conditions are 0.6MPa, and 165 °C at the age of 21 hours; the final compressive strength of cement matrix is 134.3MPa and its flexural strength is 25.9MPa (standard cured samples achieve 114.6MPa and 15.7MPa). Hydrothermal curing is even more effective for cement matrix reinforced by steel fibres (for example, the compressive strength can reach 177.5MPa, while laboratory-cured samples achieve a compressive strength of 108.5MPa).

High Strength Concrete Matrix for Textile Reinforced Concrete Production in Special Curing Conditions

2015 ◽  
Vol 824 ◽  
pp. 161-165
Author(s):  
Ondřej Holčapek
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Strength ◽  
Cement Matrix ◽  
Textile Reinforced Concrete ◽  
Curing Conditions ◽  
Concrete Production ◽  
Reinforced Cement ◽  
Curing Method ◽  
Concrete Matrix

This contribution deals with interesting and progressive curing method applied to fresh concrete matrix for textile reinforced concrete production. The application of high pressure 0.3 MPa and temperature 130 °C in 100 % humidity environment for 4 hours was performed. Cement matrix and steel fibers reinforced cement matrix has been investigated. The goal of this research is to quantified compressive strength, flexure strength, bulk density and dynamic modulus of elasticity of both mixtures. These parameters were investigated after hydrothermal curing process at the ages 6, 12, 15, 18, 21 and 24 hour after first contact of water with cement. All parameters were investigated on specimens 40 x 40 x 160 mm3 and the destructive tests were controlled by increase of deformation. Special curing condition led to an increase of the compressive strength by more than 10 % in case of cement matrix, and by more than 40 % in case of fiber reinforced cement matrix.

scholarly journals Use of Cement Suspension as an Alternative Matrix Material for Textile-Reinforced Concrete

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2127
Author(s):  
Richard Fürst ◽  
Eliška Fürst ◽  
Tomáš Vlach ◽  
Jakub Řepka ◽  
Marek Pokorný ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Epoxy Resin ◽  
High Performance Concrete ◽  
Bending Test ◽  
Resin Matrix ◽  
Cement Matrix ◽  
Sample Type ◽  
Textile Reinforced Concrete ◽  
Epoxy Resin Matrix ◽  
Four Point Bending

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.

scholarly journals Compressive Strength and Dimensional Stability of Palm Oil Empty Fruit Bunch Fibre Reinforced Foamed Concrete

2018 ◽  
Vol 65 ◽  
pp. 02001 ◽  
Author(s):  
Siong Kang Lim ◽  
Hock Yong Tiong ◽  
Kai Siong Woon
Keyword(s):  
Compressive Strength ◽  
Palm Oil ◽  
Dimensional Stability ◽  
Performance Index ◽  
Weather Condition ◽  
Drying Shrinkage ◽  
Cement Matrix ◽  
Strength Performance ◽  
Curing Conditions ◽  
Foamed Concrete

Rapid drying shrinkage is an important factor in causing cracks of concrete. This research was aimed at studying the effects of Palm Oil Empty Fruited Bunch (POEFB) fibre on the drying shrinkage behaviour and compressive strength of foamed concrete (FC) under two different curing conditions. The adopted curing conditions were air curing and tropical natural weather curing. Two volume fractions of POEFB fibre were used, which were 0.25% and 0.50% based on dry mix weight with 1-2 cm in length. The dimensional stability of the control specimen and POEFB fibre reinforced FCs was obtained by cumulating the measured linear shrinkage or expansion due to different curing conditions. The results from the two different specimens were compared. The results showed that specimens reinforced with POEFB fibre and cured under tropical natural weather condition attained lesser variations of dimensional stability and higher 90-day strength performance index than the reference mix without POEFB fibre. This improvement was attributed to the ability of POEFB fibre to bridge the cement matrix, and irregular wetting process under tropical natural weather curing condition had enabled more production of Calcium Silicate Hydrate gels that gradually blocked the penetration of water into the specimens and increased the compressive strength. It is observed that 11.43% and 4.46% of improvement in 90-day strength performance index were obtained in natural weather cured 0.5% of POEFB fibre reinforced specimen, with corresponded to the reference mix and 0.25% of POEFB fibre reinforced specimens, respectively.

Investigation of Bending Capacity of Concrete Elements Strengthened by Textile Reinforced Concrete

2016 ◽  
Vol 827 ◽  
pp. 227-230
Author(s):  
Ondřej Holčapek
Keyword(s):  
Reinforced Concrete ◽  
High Strength ◽  
Maximum Size ◽  
Cement Composite ◽  
Silica Sand ◽  
Bending Test ◽  
Experimental Program ◽  
Cement Matrix ◽  
Textile Reinforced Concrete ◽  
Bending Capacity

Presented contribution deals with using textile reinforced concrete containing newly invented high strength cement matrix for strengthening concrete structures. The issue of old concrete ́s surface interaction with newly applied slim layer of textile reinforced concrete is investigated and verified by bending test. Water to binder ration under 0.3, maximum size of used silica sand 1.2 mm, and compressive strength over 100 MPa characterize used fine grain cement matrix. Over 12 months old beams with dimension 100 x 100 x 400 mm made from ordinary concrete were used for strengthening during performed experimental program. Strengthening took place on bending side. Different number (1, 3 and 5) of textile fabrics made from alkali-resistant glass (surface density 275 g/m2) was applied into slim layer of cement composite. Increasing number of used fabrics leads to different failure mode due shearing force action.

Bond Properties of Concrete Beams Strengthened by AR-Glass Textile and Basalt Textile Reinforced Concrete

2016 ◽  
Vol 825 ◽  
pp. 7-10 ◽  
Author(s):  
Ondřej Holčapek ◽  
Filip Vogel
Keyword(s):  
Reinforced Concrete ◽  
Surface Density ◽  
Concrete Beams ◽  
High Strength ◽  
Bending Test ◽  
Cement Matrix ◽  
Textile Reinforced Concrete ◽  
Fine Grain ◽  
Fabric Surface ◽  
Textile Fabric

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.

scholarly journals Experimental Study on Deformation Behavior and Compressive Strength of Concrete Cast in Steel Tube Arches under Low-Temperature Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tuo Shi ◽  
Nianchun Deng ◽  
Xiao Guo ◽  
Wen Xu ◽  
Shi Wang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
Performance Test ◽  
Large Diameter ◽  
Test Site ◽  
Steel Tube ◽  
Design Strength ◽  
Curing Conditions ◽  
Expansive Agent ◽  
Arch Bridges

Taking the construction of a concrete-filled steel tube (CFST) arch bridge (part of the Sichuan-Tibet Railway) in low temperatures as the test site, firstly the deformation performance test of concrete was carried out. Following this initial testing, measurement of compressive strength and shrinkage performance was conducted in large-diameter CFSTs under a variety of curing conditions. Experimental results showed that the expansion effect of Ca-Mg composite expansive agent in concrete was better than that of other expansive agents at any stage. Under low-temperature curing (0°C), the sampling strength of the large-diameter CFSTs reached 73.5% of the design strength at 28 d in the presence of a nonthermal curing system. The design strength itself was reached, when a curing system involving a thermal insulation film was applied, and use of this film also led to improvements in concrete shrinkage. The results suggested that a Ca-Mg composite expansive agent, combined with an insulation film curing system, should be the technique selected for concrete pumping construction of CFST arch bridges in Tibet.

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