Use of Polymer for Rehabilitation of Uneven Settlement in Concrete Roadbed Slabs of Tunnels

2015 ◽  
Vol 1129 ◽  
pp. 468-473
Author(s):  
Jing Liu ◽  
Xin Guo Zheng ◽  
Shu Ming Li ◽  
Zhi Zeng ◽  
De Jun Yang ◽  
...  
Keyword(s):  
High Strength ◽  
Strength Properties ◽  
Test Results ◽  
Polymer Injection ◽  
Railway Tracks ◽  
Low Viscosity ◽  
Compressive Strength Test ◽  
Injection Technology

In some tunnels of railway lines located in water-rich region, due to the long-term water leakage and erosion, the foundation of railway lines showed large uneven settlement deformation, so the above concrete roadbed slabs also experienced uneven settlement accordingly. The smoothness of railway tracks diminished, and the speed of passing trains had to be limited to ensure safety. To restore the smoothness of the tracks, a dedicated polymer injection technology for quick uplift rehabilitation of uneven settlement concrete roadbed slabs was studied on site just within the specified daily skylight time (about 3 hours every day) of the railway lines. A hydrophobic polymer with low-viscosity, quick-setting and high-strength properties was used for injecting, filling and uplifting the concrete slabs in water-rich foundations. The high-precision electronic levels were adopted to monitor rising height of the tracks in real time. After rehabilitation, the filling quality of polymer injection under roadbed slabs was examined using Φ50 mm core samples and the strength of hardened polymer was verified by compressive strength test. Results indicated that the polymer could uplift the concrete roadbed slabs effectively and restore the smoothness of railway tracks accurately even in the water-rich environment. The research can provide some valuable references for quick rehabilitation of uneven settlement concrete roadbed slabs in water-rich tunnels.

Clinical Features of PTSD and Adjustment Disorders in Refugees from the Zone ATO

2017 ◽  
Vol 41 (S1) ◽  
pp. S725-S725
Author(s):  
H. Kozhyna ◽  
V. Korostiy ◽  
V. Mykhaylov
Keyword(s):  
Emotional Disorders ◽  
Clinical Features ◽  
Trait Anxiety ◽  
Adjustment Disorders ◽  
Test Results ◽  
Medical Institutions ◽  
Reactive Anxiety ◽  
Competing Interest

AimTo study clinical features of PTSD and adjustment disorders in refugees from the zone ATO.MethodsWe have a complex psychopathological and psychodiagnostic research 156 refugees in volunteer center in Kharkiv.ResultsAmong the IDPs observed, 75.9% have violations of adaptation: long-term depressive reaction and predominant disturbance of other emotions. The men reactive alarm indicators (average – 37.7 ± 3.0), were higher than trait anxiety (average – 32.6 ± 2.9). On the contrary, women figures trait anxiety (average – 38.6 ± 2.9) were higher than reactive anxiety (average – 34.7 ± 3.0). Severity of depressive symptoms also slightly prevailed in women. The mean score on the Hamilton scale for men was 17.0 ± 2.3 points, women – 18.0 ± 2.3 points.Test results on a scale of quality of life showed no significant differences between men and women. We have developed a medical and psychological support system to correct the neurotic disorders in refugees.ConclusionsThe majority of people who left the ATO zone have psycho-emotional disorders of different severity and require a further correction in the specialized medical institutions.Disclosure of interestThe authors have not supplied their declaration of competing interest.

scholarly journals Multigene Genetic Programming for Estimation of Elastic Modulus of Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alireza Mohammadi Bayazidi ◽  
Gai-Ge Wang ◽  
Hamed Bolandi ◽  
Amir H. Alavi ◽  
Amir H. Gandomi
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Genetic Programming ◽  
High Strength Concrete ◽  
Elastic Moduli ◽  
High Strength ◽  
Test Results ◽  
Strength Concrete ◽  
Multigene Genetic Programming ◽  
Compressive Strength Test

This paper presents a new multigene genetic programming (MGGP) approach for estimation of elastic modulus of concrete. The MGGP technique models the elastic modulus behavior by integrating the capabilities of standard genetic programming and classical regression. The main aim is to derive precise relationships between the tangent elastic moduli of normal and high strength concrete and the corresponding compressive strength values. Another important contribution of this study is to develop a generalized prediction model for the elastic moduli of both normal and high strength concrete. Numerous concrete compressive strength test results are obtained from the literature to develop the models. A comprehensive comparative study is conducted to verify the performance of the models. The proposed models perform superior to the existing traditional models, as well as those derived using other powerful soft computing tools.

Study on the Compressive Strength and Mixing of Ultra-High Performance Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 825-828
Author(s):  
Su Li Feng ◽  
Peng Zhao
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Properties ◽  
Test Method ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Ultra High Performance Concrete ◽  
Mixture Ratio

The test in order to obtain liquidity, higher intensity ultra-high performance concrete(UHPC), in the course of preparation, high intensity quartz sand to replace the ordinary sand,reasonable mixture ratio control low water-cement ratio,the incorporation of part of the test piece ofsteel fibers, produced eight specimens . In the ordinary molding and the standard conservation 28d thecase, the ultra-high-performance concrete compressive strength of more than 170MPa.Thepreparation of the test method and test results will provide the basis for further study of the law of themechanical properties of ultra high strength properties of concrete.

scholarly journals THE EFFECT OF ADDING CEMENT WASTE ON THE QUALITY OF CONCRETE COMPRESSIVE

Jurnal CIVILA ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 213
Author(s):  
Asrul Majid ◽  
Hammam Rofiqi Agustapraja
Keyword(s):  
Compressive Strength ◽  
Strength Test ◽  
Fine Aggregate ◽  
Infrastructure Development ◽  
Test Results ◽  
Compressive Strength Test ◽  
Compressive Strength Of Concrete ◽  
Concrete Materials ◽  
Test Objects

Infrastructure development is one of the important aspects of the progress of a country where most of the constituents of infrastructure are concrete. The most important constituent of concrete is cement because its function is to bind other concrete materials so that it can form a hard mass. The large number of developments using cement as a building material will leave quite a lot of cement bags.In this study, the authors conducted research on the effect of adding cement waste to the compressive strength of concrete. This study used an experimental method with a total of 24 test objects. The test object is in the form of a concrete cylinder with a diameter of 15 cm and a height of 30 cm and uses variations in the composition of the addition of cement waste cement as a substitute for fine aggregate, namely 0%, 2%, 4% and 6%. K200). The compressive strength test was carried out at the age of 7 days and 28 days.The test results show that the use of waste as a partial substitute for fine aggregate results in a decrease in the compressive strength of each mixture. at the age of 7 days the variation of 2% is 16.84 MPa, 4% is 11.32 MPa and for a mixture of 6% is 6.68 MPa. Meanwhile, the compressive strength test value of 28 days old concrete in each mixture decreased by ± 6 MPa. So the conclusion is cement cement waste cannot be used as a substitute for fine aggregate in fc 16.6 (K200) quality concrete because the value is lower than the specified minimum of 16.6 MPa.

scholarly journals PENGARUH TEKANAN BAHAN BAKAR TERHADAP EMISI GAS BUANG PADA MESIN K3-VE

Otopro ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 23
Author(s):  
Heru Arizal ◽  
Ali Hasbi Ramadani ◽  
Ferly Isnomo Abdi
Keyword(s):  
Engine Speed ◽  
Fuel Injection ◽  
Quantitative Description ◽  
Exhaust Emissions ◽  
Test Results ◽  
Use Of Technology ◽  
Exhaust Gas Emission ◽  
Injection Technology ◽  
Motorized Vehicles

One of the causes of air pollution today is the increasing use of motorized vehicles. The use of technology has also been pinned on many wrong vehicles to improve the quality of the exhaust emissions that have been produced. One of them is EFI (Electronic Fuel Injection) technology which has been embedded in many vehicles. The component that has an effect on improving the quality of exhaust emissions at EFI is an electronic fuel pump. The fuel pressure on the electronic pump can be adjusted manually. This study aims to determine changes in fuel pressure on exhaust gas emission levels. This research uses an experimental method, where the fuel pressure is varied from the pressure of 50psi, 40psi, 30psi and 20psi, and the engine speed is varied from 800rpm, 1500rpm, 2250rpm, 3000rpm and 3750rpm. The results of the data obtained are analyzed using the quantitative description method. The test results showed that there was a decrease in the lowest CO level of 0.663% at 30psi fuel pressure with 3750rpm engine speed. HC also experienced a decrease, the lowest decrease was obtained in the value of 280ppm at 20psi fuel pressure and 3750rpm engine speed. While CO2 has increased, the highest increase of 13.33% was achieved at 20psi fuel pressure and 3750rpm engine speed.

Test Study of Compressive Strength of High-Strength Stone Masonry

2011 ◽  
Vol 71-78 ◽  
pp. 3794-3799
Author(s):  
Da Lin Hu ◽  
Long Gang Chen ◽  
Feng Chen
Keyword(s):  
Compressive Strength ◽  
High Strength ◽  
Stone Masonry ◽  
Test Results ◽  
Aggregate Concrete ◽  
Long Span ◽  
Test Study ◽  
Compressive Strength Test ◽  
Concrete Joints ◽  
Arch Bridges

Stone masonry with micro-aggregate concrete joints has been widely used in long span arch bridges in China. However, the mechanical properties of this kind of high-strength masonry have been seldom studied. This paper presents compressive strength test study of eight groups of masonry specimens, which consist of C30 or C40 micro-aggregate concrete joints and five kinds of dressed stone blocks. The masonry mechanical behavior is described and test results are analyzed. An empiric formula of the masonry compressive strength is obtained. Finally, design value of masonry compressive strength is assessed and discussed.

Influence of Metakaolin on Strength and Microstructure of Steam-Cured High-Strength Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 42-46 ◽  
Author(s):  
Jun Jie Zeng ◽  
Zhi Hong Fan ◽  
Long Chen
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Pozzolanic Reaction ◽  
Early Age ◽  
Test Results ◽  
Replacement Level ◽  
Strength Concrete ◽  
Pozzolanic Reactivity ◽  
Compressive Strength Test

The influence of metakaolin (MK) on strength and microstructure of steam-cured high-strength concrete has been investigated using compressive strength test, XRD, MIP and SEM. Three MK replacement levels were considered in the study: 5%, 10% and 15% by weight of cement. A mix double blended with 10% MK and 10% slag was prepared too. Test results have indicated that MK can increase the compressive strength of steam-cured concrete, especially at early age. Compressive strength up to 90MPa at 1 and 28 days is obtained with the incorporation of 10% MK and 10% slag. When the replacement level of MK is higher than 10%, the enhancement of strength becomes less significant. Content of Ca (OH)2 crystals is decreased while content of hydrates with Al is increased due to the pozzolanic reactivity of MK. Concrete pore structure is significantly refined and a denser hydrates structure is obtained due to the pozzolanic reaction and filler effect of MK. Meanwhile, combination of aggregate and paste is enhanced too. The improvements of strength and microstructure become more obvious when MK and slag are double incorporated.

scholarly journals Calculation of the normal section strength of rubcon beams using deformation diagrams

2019 ◽  
Vol 135 ◽  
pp. 03067
Author(s):  
Aleksei Polikutin ◽  
Yuri Potapov ◽  
Artem Levchenko
Keyword(s):  
Cross Sections ◽  
High Strength ◽  
Strength Properties ◽  
Polymer Concrete ◽  
Test Results ◽  
Pure Bending ◽  
Normal Section ◽  
Rubber Concrete ◽  
Disperse Reinforcement ◽  
Deformation Diagrams

Rubber concrete (rubcon) - polymer concrete, which has high strength properties, as well as the constructions made of it. Fibrorubcon – rubber concrete with the addition of disperse reinforcement. On the basis of test results for pure bending, empirical dependencies and prerequisites for adapting existing methods for calculating the strength of normal sections of rubcon and fibrorubcon beams were obtained. These studies allow developing methods for calculating the normal cross sections of bending elements made of rubber concrete using deformation diagrams and taking into account the work of stretched polymer concrete.

Surface Roughness Research in Turning of Damage-Tolerant Titanium Alloy

2014 ◽  
Vol 633-634 ◽  
pp. 743-746
Author(s):  
Tao Sun ◽  
Zhuo Chen
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Predictive Model ◽  
High Reliability ◽  
Orthogonal Experiment ◽  
High Strength ◽  
Test Results ◽  
Urgent Problem ◽  
Damage Tolerant

TC21 is a first high strength and damage-tolerant titanium alloy self-developed in China, which has independent intellectual property. As it is known to all, titanium alloy TC21 is one of the most widely used materials in aerospace. The improvement of cutting quality of titanium alloy is an urgent problem. In this paper, the orthogonal experiment were carried out to study surface roughness of turning TC21. The predictive model of surface roughness in turning TC21 was built by analysis of multivariable linear regression on the basis of experiment. Statistical test results indicated the established predictive model were in highly notable test status and had high reliability. These works provide references for machining TC21.

Structural design of pressure pipes

2001 ◽  
Vol 1 (3) ◽  
pp. 107-115
Author(s):  
I. Bjorklund
Keyword(s):  
Structural Design ◽  
High Strength ◽  
Strength Properties ◽  
Pipe Material ◽  
Working Pressure ◽  
Pressure Pipes ◽  
Flexible Pipes ◽  
Glass Fibre Reinforced ◽  
Design Calculations

There exist various methods for structural design of buried pressure pipes. However, it must be remembered that sophisticated design methods needs a significant supervision of the construction work to be reliable. The need for detailed calculations varies for different materials. Ductile iron (DCI) pipes have high strength properties and for most DCI pipe installations a design check against EN 545 is fully sufficient as regards the structural design. Glass fibre reinforced polyester (GRP) pipes have a limited strainability and are thus highly dependent on the quality of the installation work. It is recommendable to check that the combined strain of the load cases which the pipe shall be designed for does not exceed the allowable strain for the pipe material. Polyethylene (PE) and Polyvinylchloride (PVC) pipes are flexible pipes with a high strainability. The allowable working pressure for these pipes will normally be determined by the PN class and the operating temperature and the need for structural design calculations is limited. It is interesting to note that PE pipes which have the lowest strength properties of all of the above mentioned materials have the lowest failure rate. The latter shows that it is not just the tensile strength, but other factors such as strainability and corrosion resistance which affect the structural performance of buried pipelines.

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