Detection of Reinforced Concrete Crack Using Mechano-Luminescence Paint

2013 ◽  
Vol 316-317 ◽  
pp. 1049-1054 ◽  
Author(s):  
Il Young Jang ◽  
Seong Kyum Kim ◽  
Ji Sik Kim ◽  
Ki Yong Ann ◽  
Chang Geun Cho
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Propagation Speed ◽  
Bending Test ◽  
Reinforced Concrete Structures ◽  
Concrete Material ◽  
Concrete Crack ◽  
Concrete Materials ◽  
Crack Propagation Speed

As a nonuniform and unisotropic material with a relatively low tensile strength in spite of high compression strength, a concrete material is vulnerable to bending and tension. Due to the mechanical properties of the current reinforced concrete structures, it is hard for concrete materials to avoid the damages caused by cracks. Although cracks are the easiest things to detect and the most effectively repairable things due to their characteristics, it is very hard to measure them efficiently. In this research, the author measured cracks by visualizing them through mechano- luminescence(ML) paint. By applying ML paint on the surface of the specimen and using the 3-point bending test, the author conducted a quantitative evaluation on the mechanical properties of cracks such as the cracking aspect and length of reinforced concrete. Through the results of this research, the author confirmed the crack propagation speed by section and the mechanical correlation such as between loads and cracks and between deflection and cracks, which means this research was quite successful in analyzing the characteristics of cracks.

Simulation on Expanding Crack of Reinforced Concrete Based on Franc2d

2011 ◽  
Vol 105-107 ◽  
pp. 1027-1030
Author(s):  
Yue Shun Chen ◽  
Li Liu
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Limit State ◽  
Protective Layer ◽  
Propagation Speed ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Concrete Cracking ◽  
Slope Change ◽  
Crack Propagation Speed

It is a key point of durability deterioration to reinforced concrete structures that protective layer concrete cracking, so it is essential to assess the durability limit state to determine the critical corrosive ratio. In this paper the Franc2D tool has been used to simulate the corrosive expanding process of protective layer concrete in reinforced concrete structure, and the slope change of the ρ-CMOD curve has been used as the basis to determine the critical corrosive ratio, then the effects of stirrups to critical corrosive ratio and the corrosive expanding crack width has been studied. It has been showed a linear relationship between the corrosive ratio and crack width, and appearance of corrosive expanding cracks has been delay with the stirrups, on the other hand crack propagation speed can be reduced with the stirrups across cracks effectively.

scholarly journals Determination of Mechanical Properties of Fiber Reinforced Concrete for Numerical Modelling

2020 ◽  
Vol 16 (1) ◽  
pp. 86-106
Author(s):  
Z. Marcalikova ◽  
R. Cajka
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Numerical Modelling ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
Fiber Reinforced ◽  
Flexural Tensile Strength

AbstractThe paper deals with the determination of mechanical properties of fiber reinforced concrete in dependence on various dosages and recipe of concrete. The mechanical properties were determined for the default recipe of concrete, where the individual variants differ in the amount of fibers. The fibers dosing was 0, 25, 50 and 75 kg/m3. At the highest dosage of 75 kg/m3, the recipe is optimized with regard to the microstructure of the concrete. In the experimental program were determined compressive strength, modulus of elasticity, split tensile strength, flexural tensile strength and load-displacement diagram. The flexural tensile strength was determined based on a three-point and four-point bending test. Based on the evaluated data, the uniaxial tensile strength and the functional dependence for the resultant recipe of concrete with a dosage of 75 kg/m3 is with respect of the increasing importance and application of numerical modelling of building structures, the analysis is performed using non-linear calculation. The aim was to simulate the performed laboratory test and appropriately approximate the specific input parameters of the fiber reinforced concrete for nonlinear analysis.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

Influence of the Composition of Cement Mortars Modified by Lime or Polymers on the Mechanical Properties and Microstructure of Mortars

2013 ◽  
Vol 592-593 ◽  
pp. 647-650 ◽  
Author(s):  
Małgorzata Lenart
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Polymer Composites ◽  
Adhesion Strength ◽  
Hardened Cement ◽  
Cement Mortars ◽  
Styrene Butadiene

Cement – polymer composites are nowadays widely used in repair systems not only in case of concrete or reinforced concrete constructions but also in masonry. Polymers addition for example already at 5% m.c. modifies the structure of the cement – polymer composite in a way that many of the mechanical properties such as flexural strength, tensile strength or adhesion to substrates are improved. The paper presents the results of tests such as flexural, compressive or adhesion strength to ceramic substrate of hardened cement mortars with different composition, as well as selected cement mortars modified by two polymers: polyvinyl alcohol and styrene – butadiene polymer dosed at 5 % m.c. Four types of cement mortars modified by lime (component used in historical constructions as well as in contemporary masonry mortars) are also examined for comparison.

RETROFITTING PERFORMANCE OF REINFORCED CONCRETE ONE WAY SLAB

2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Norliyati Mohd Amin ◽  
Nur Aqilah Aziz ◽  
Ilya Joohari ◽  
Anizahyati Alisibramulisi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Strength Performance ◽  
Concrete Crack ◽  
Reinforced Polymer ◽  
Structural Capacity

Cracks in concrete structure have always been a big threat on the strength of the concrete. Crack is one of the common deterioration observed in reinforced concrete beams and slabs. Concrete cracking is a random process, highly variable and influenced by many factors. To restore the structural capacity of the concrete damages, retrofitting and strengthening are required. There are several techniques that are used for retrofitting and strengthening reported in the literature [1], [2], [3]. This paper investigates the strength performance of retrofitting and strengthening methods of reinforced concrete one-way slab. Flexural bending test are performed on three different concrete slab of size 1000 mm x 500 mm x 75 mm. The methods that are used for retrofit are epoxy injection and patching and for the strengthening is lamination of carbon fiber reinforced polymer. The slabs were loaded to a certain stage where the cracks were formed for retrofitting and strengthening procedure. The achieved failure mode and load capacity of the concrete slab were observed. The repaired techniques for restoring and improving the structural capacity of cracked concrete slabs were analyzed. The ultimate load achieved for the epoxy injection laminate was 19.60 kN followed by CFRP laminate and patching that were 17.64 kN and 17.03 kN respectively. While the deflection value for the three specimens were 14.42 mm, 4.49 mm and 7.036 mm.  

Production and Use of the Textile Reinforced Concrete

2014 ◽  
Vol 982 ◽  
pp. 59-62 ◽  
Author(s):  
Filip Vogel
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
High Strength ◽  
Cement Matrix ◽  
High Tensile Strength ◽  
Textile Reinforced Concrete ◽  
Corrosion Resistant ◽  
New Material ◽  
Ductile Behavior

This article discusses about the textile reinforced concrete. The textile reinforced concrete is a new material with great possibilities for modern construction. The textile reinforced concrete consists of cement matrix and textile reinforcement of high strength fibers. This combination of cement matrix and textile reinforcement is an innovative combination of materials for use in the construction. The main advantage of the textile reinforced concrete is a high tensile strength and ductile behavior. The textile reinforced concrete is corrosion resistant. With these mechanical properties can be used textile reinforced concrete in modern construction.

scholarly journals FLEXURAL REINFORCED CONCRETE ELEMENTS NORMAL SECTION BEARING CAPACITY EVALUATION IN FRACTURE STAGE

2017 ◽  
Vol 9 (2) ◽  
pp. 70-78 ◽  
Author(s):  
Justas SLAITAS ◽  
Zbynek HLAVAC ◽  
Arnoldas ŠNEIDERIS
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Crack Depth ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Assessment Process ◽  
Reinforced Concrete Structures ◽  
Compression Zone ◽  
Normal Section

This article examines flexural reinforced concrete structures condition assessment process in existing buildings on the stage where the reinforcement stress is between the yield and the tensile strength. The research is made on V. Jokūbaitis proposed methodology directly measuring the compression zone height, allowing us to evaluate the behavior of reinforced concrete beam fracture sufficiently precisely. This paper confirms the hypothesis that, when reinforcement reaches yielding stress, elastic strain dominates in concrete‘s compression zone and it is reasonable to use triangular concrete compression zone diagram, without tensile concrete above crack evaluation. The methodology of reinforced concrete structures bearing capacity assessment according to limit normal section crack depth is proposed. There is established connection between bending moments, when reinforcement achieve yielding stress and tensile strength, which allows us to decide about structures bearing capacity reserve. The results are confirmed with experimental studies and calculated values obtained by methodologies based on different reduced stress diagrams of concrete‘s compressive zone.

scholarly journals Experimental Study on Mechanical Properties of High Performance Hybrid Fiber Concrete for Shaft Lining

2021 ◽  
Vol 11 (17) ◽  
pp. 7926
Author(s):  
Qian Zhang ◽  
Wenqing Zhang ◽  
Yu Fang ◽  
Yongjie Xu ◽  
Xianwen Huang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Reference Group ◽  
Splitting Tensile Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Fiber Concrete ◽  
Shaft Lining

In order to solve the problem of highly brittle shaft lining under dynamic loading, a combination of hybrid fiber concrete mixed with steel and polypropylene fiber is proposed to make shaft lining. C60, the concrete commonly used in shaft lining, was selected as the reference group. The static mechanical properties, dynamic mechanical properties, and crack failure characteristics of the hybrid fiber concrete were experimentally studied. The test results showed that compared to the reference group concrete, the compressive strength of the hybrid fiber-reinforced concrete did not significantly increase, but the splitting tensile strength increased by 60.4%. The split Hopkinson compression bar results showed that the optimal group peak stress and peak strain of the hybrid fiber concrete increased by 58.2% and 79.2%, respectively, and the dynamic toughness increased by 68.1%. The strain distribution before visible cracks was analyzed by the DIC technology. The results showed that the strain dispersion phenomenon of the fiber-reinforced concrete specimen was stronger than that of the reference group concrete. By comparing the crack failure forms of the specimens, it was found that compared to the reference group concrete, the fiber-reinforced concrete specimens showed the characteristics of continuous and slow ductile failure. The above results suggest that HFRC has significantly high dynamic splitting tensile strength and compressive deformation capacity, as well as a certain anti-disturbance effect. It is an excellent construction material for deep mines under complex working conditions.

scholarly journals SCOPE OF IMPROVING MECHANICAL CHARACTERISTICS OF CONCRETE USING NATURAL FIBER AS A REINFORCING MATERIAL

2020 ◽  
Vol 32 (2) ◽  
Author(s):  
Sristi Das Gupta ◽  
MD Shahnewaz Aftab ◽  
Hasan Mohammod Zakaria ◽  
Chaity Karmakar
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Synthetic Fiber ◽  
Jute Fiber ◽  
Fiber Reinforced ◽  
Plastic Shrinkage ◽  
Shrinkage Cracks ◽  
Reinforcing Material

Using natural (Jute) fiber in concrete as a reinforcing material can not only augment the concrete strength but also restrict the use of synthetic fiber which is environmentally detrimental. To achieve this goal, this study evaluated compressive strength, tensile strength and plastic shrinkage of concrete incorporating ‘Natural (Jute)’ fiber of different length (15 mm and 25 mm) with various mix proportions of 0.10%, 0.2%, 0.3% and 0.4% respectively by volume of concrete. Concrete is vulnerable to grow shrinkage cracks because of high evaporation rate in dry and windy conditions. Incorporating of fibers could abate development of this crack. The large length (25 mm) and higher content ( 0.3%) of reinforcing materials (jute fiber) result to the lowering of mechanical properties of JFRC compare to plain concrete. But in the incorporation of short (15 mm) and low fiber content ( 0.3%), enhances the mechanical properties of the same JFRC. Inclusion of 0.3% (15 mm length) fiber gave maximum enhancement of both concrete compressive and tensile strength by 12.4% and 58% respectively compared to the non-fiber reinforced concrete. A drastic suppression of crack occurrence and area of crack between non-fiber reinforced concrete and fiber reinforced concretes was attained. Experimental results of incorporating 0.1–0.4% fiber with 15 mm length in concrete revealed that plastic shrinkage cracks were decreased by 75–99% in contrast to non-fiber reinforced concrete. Therefore, it is concluded that the incorporation of jute fiber in making FRC composite would be one of the favorable methods to enhance the performance of concrete.

scholarly journals Historical reinforced concrete structures – used materials and calculating algorithms

2015 ◽  
Vol 14 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Bartosz Szostak ◽  
Maciej Trochonowicz
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Structural Element ◽  
Historical Building ◽  
Historical Material ◽  
Low Strength ◽  
Concrete Elements

During designing in historical object we can have a problem with historical reinforced concrete elements. Many designers, classifies this elements as low strength. They are convicted that this type of elements in historical building can be only a monument and cannot be used in this construction as an structural element. It is very important in this type of buildings to keep as many historical material as it is possible. Authors researched the literature which has been a guide in the design and execution of these elements. By comprising used algorithms and physico-mechanical properties of old materials with algorithms and materials, which are using today, we are able to estimate the strength of such elements.

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