scholarly journals Concrete Crack Width Detecting System for Android Platform

2015 ◽  
Vol 9 (1) ◽  
pp. 846-851
Author(s):  
Chen Shuang-rui ◽  
Shi Zheng ◽  
Yan Quan-sheng
Keyword(s):  
Mobile Phone ◽  
Crack Width ◽  
Concrete Beam ◽  
Measuring System ◽  
Concrete Crack ◽  
Maximum Crack ◽  
Crack Detector ◽  
Processing Techniques ◽  
Edge Recognition ◽  
Test Result

In order to measure crack width accurately and automatically, an Android-based Automatic Crack Width Measuring System (ACWMS) has been developed, taking advantage of the high portability of Android devices. After capturing the image using mobile phone camera, the image is processed by image processing techniques, including graying, binaryzation, denoising and edge recognition. A specified algorithm is executed to calculate the crack width according to the provided edge data. Measurements has been done to each of the 10 cracks in the same concrete beam, using Samsung Galaxy S3 mobile phone and WYSX-40X Crack detector, respectively. Test result shows that the maximum crack width accuracy reaches 95.26%, which satisfies the construction needs. Therefore, this system can greatly improve the efficiency and accuracy during crack width measurement.

scholarly journals CRACK ANALYSIS OF CFRP REINFORCED CONCRETE BEAMS UNDER SECONDARY LOADING

2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Jinliang Liu ◽  
Jiawei Wang ◽  
Yanmin Jia
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Crack Spacing ◽  
Reinforced Concrete Beams ◽  
Calculation Formula ◽  
Plate Area ◽  
Average Crack ◽  
Maximum Crack

The paper established the calculation formulas on the average crack spacing and the maximum crack width of CFRP（Carbon Fiber Reinforced Polymer）reinforced concrete beam under the secondary loading. Conversion of CFRP plate area into the reinforcement ratio of the reinforced beam, the calculation formula on the average crack spacing of CFRP reinforced concrete beam under the secondary loading was established. On basis of the calculation formula on the maximum crack width of concrete beam, the calculation formula on the maximum crack width of CFRP reinforced concrete beam under the secondary loading was established. The average crack spacing and the maximum crack width calculated by the formulas in the paper were compared with the test data, it was verified that the formula is correct.

scholarly journals Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

2020 ◽  
Author(s):  
Jadin Zam S. Doctolero ◽  
Arnel B. Beltran ◽  
Marigold O. Uba ◽  
April Anne S. Tigue ◽  
Michael Angelo B. Promentilla
Keyword(s):  
Image Analysis ◽  
Crack Width ◽  
Ultrasonic Pulse ◽  
Self Healing ◽  
Weak Effect ◽  
Bacterial Cultures ◽  
Healing Agent ◽  
Optimum Response ◽  
Maximum Crack ◽  
Cultured Bacteria

A sustainable solution for crack maintenance in geopolymers is necessary if they are to be the future of modern green construction. This study thus aimed to develop self-healing biogeopolymers that could potentially rival bioconcrete. First, a suitable healing agent was selected from Bacillus subtilis, B. sphaericus, and B. megaterium by directly adding their spores in the geopolymers and subsequently exposing them to a large amount of nutrients for 14 days. SEM-EDX analysis revealed the formation of biominerals for B. subtilis and B. sphaericus. Next, the effect of biochar-immobilization and co-culturing (B. sphaericus and B. thuringiensis) on the healing efficiencies of the geopolymers were tested and optimized by measuring their ultrasonic pulse velocities weekly over a 28-day healing period. The results show that using co-cultured bacteria significantly improved the observed efficiencies, while biochar-immobilization had a weak effect but yielded an optimum response between 0.3-0.4 g/mL. The maximum crack width sealed was 0.65 mm. Through SEM-EDX and FTIR analyses, the biominerals precipitated in the cracks were identified to be mainly CaCO3. Furthermore, image analysis of the XCT scans of some of the healed geopolymers confirmed that their pulse velocities were indeed improving due to the filling of their internal spaces with biominerals. With that, there is potential in developing self-healing biogeopolymers using biochar-immobilized spores of bacterial cultures.

scholarly journals Numerical Modeling of Nonuniform Corrosion-Induced Concrete Crack Width

2018 ◽  
Vol 144 (8) ◽  
pp. 04018120 ◽  
Author(s):  
Shangtong Yang ◽  
Xun Xi ◽  
Kefei Li ◽  
Chun-Qing Li
Keyword(s):  
Numerical Modeling ◽  
Crack Width ◽  
Concrete Crack

Research on Influences of the Coarse Aggregate Size on the Cracks of the Reinforced Beam

2012 ◽  
Vol 503-504 ◽  
pp. 832-836
Author(s):  
Hong Quan Sun ◽  
Jun Ding
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Aggregate Size ◽  
Reinforced Concrete Beams ◽  
Static Loads ◽  
Reinforced Beams ◽  
Maximum Crack

This paper gives the influences of the coarse aggregate size on the cracks of the beam with different aggregate sizes under static loads. The coarse aggregate sizes are ranked into three classes: small size (4.75mm ~ 19mm), big size (19mm ~ 37.5mm) and mixed size (4.75mm ~ 37.5mm). The developments of cracks of three reinforced concrete beams with the different of coarse aggregate sizes under the static loads are researched. The results show that under the action of the same loads, The reinforced concrete beams with the big aggregate size and mixed aggregate size have almost the same maximum crack width, while the maximum crack width of the beam with small aggregate size is less than formers. Using fractal theory, the fractal dimension of the cracks is studied. The result shows that the aggregate sizes have significant effect to the cracks on the reinforced beams.

THE REINFORCED CONCRETE BEAM DEFLECTION AND CRACKING BEHAVIOR WITH ADDITIONAL FIBER STEEL

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Faisal Ananda ◽  
Agoes Soehardjono ◽  
Achfas Zacoeb ◽  
Gunawan Saroji
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Beam Deflection ◽  
Cracking Behavior ◽  
Classic Theory

The classic theory mentions that the assessment of deflection and crack width should be taken to minimize those two behaviors. This research itself has the objective to examine whether the additional fiber steel and increased reinforcement ratio has any significant impact on the deflection and existing crack width. This test used the reinforced concrete beams with a size of 15 cm x 25 cm x 180 cm which placed on a simple pedestal. The test was done gradually in every 108 kg until the reinforced yield reached. The fiber increased from 0%, 1.57%, 3.14% and 4.71% while the performance rebar ratio increased from 2 # 10, 2 # 12, and 2 # 14. The result shows that additional 4.71% of maximum fiber decrease compressive strength and rupture modulus while the tensile strength increased. The additional fiber reached a maximum in 4.71% and the additional diameter of 10 mm, 12 mm, and 14 mm increased the deflections and crack width.

Study on Mechanical Properties of Corroded Reinforced Concrete Using Support Vector Machines

2014 ◽  
Vol 578-579 ◽  
pp. 1556-1561 ◽  
Author(s):  
Shuai Yang ◽  
Cong Qi Fang ◽  
Zhi Jie Yuan
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Support Vector Machines ◽  
Crack Width ◽  
Black Box ◽  
Reduction Factor ◽  
Support Vector ◽  
Regression Formula ◽  
Vector Machines ◽  
Maximum Crack

The mechanical properties of corroded reinforced concrete under repeated load are investigated. The maximum crack width, mid-span deflection and reduction factor are predicted by using support vector machines. The maximum crack width and deflection are predicted by the black-box modeling based on support vector machines with the radial basis function kernel function. The reduction factor is predicted by using piecewise regression formula, whole regression formula and black-box modeling, respectively. The proposed prediction method is verified by comparing all prediction results with the experimental values. It is shown that the proposed method has high prediction accuracy, extensive applicable range and many predictive strategies.

Experimental Research on Bending Performance of Concrete Beams Reinforced with CFRP-PCPs Composite Rebars

2013 ◽  
Vol 438-439 ◽  
pp. 804-806
Author(s):  
Jiong Feng Liang ◽  
Jian Bao Wang ◽  
Jian Ping Li
Keyword(s):  
Experimental Research ◽  
Prestressed Concrete ◽  
Crack Width ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Experimental Results ◽  
Flexural Behavior ◽  
Bending Performance ◽  
Reinforced Beams

The flexural behavior of concrete beams reinforced with CFRP-PCPs composite rebars was studied. Experimental results showed that the deflection of beams reinforced with highly prestressed prisms is at service loads coMParable to deflection of steel reinforced beam. Flexural cracks of CFRP-PCPs composite rebars reinforced beams are hairline before prism cracking, and widened after the prism cracking. When the concrete beam was reinforced with the prestressed concrete prisms, the crack width decreased as the prestress in the prism increased.

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