Theoretical Calculation and Experimental Research of Shrinkage of High Strength Concrete an High-Speed Railway Bridges

2014 ◽  
Vol 1079-1080 ◽  
pp. 312-317
Author(s):  
Ming Zhou Gao ◽  
Ji Hua Li ◽  
Ru Deng Luo ◽  
Hai Long Wang
Keyword(s):  
High Strength Concrete ◽  
High Speed ◽  
Field Tests ◽  
High Strength ◽  
Concrete Bridges ◽  
High Speed Railway ◽  
Strength Concrete ◽  
Concrete Shrinkage ◽  
Tests And Measurements ◽  
Shrinkage Effect

Concrete bridges on high-speed railway are usually constructed with high strength concrete. Because of shrinkage of concrete, large stress and deformation always appear in construction and operation process of bridges. It even leads to concrete cracking. So as to guarantee the safety of structures and smoothness of tracks, correct calculation of concrete shrinkage effect must be done. Concrete shrinkage effect is a very complex non-stress strain problem which is influenced by numerous factors and difficult to calculate. According to the factors considered from different emphasis aspects, a variety of patterns or specifications are formed based on different domestic and foreign models of concrete shrinkage calculation. Combined with the construction of Jiangshan Harbor Bridge (75+2×135+75) m prestressed concrete continuous beam bridge on Hangzhou-Changsha high-speed railway, concrete shrinkage field tests and measurements were carried in which the same mix of high strength concrete as that of the bridge was used. The results of tests and measurements were compared with results of different theoretical models. The effects of high strength concrete shrinkage on high-speed railway concrete bridges were studied and some useful conclusions were obtained.

scholarly journals Nanomodified rapid hardening concretes reinforced with dispersed basaltic fibers

2021 ◽  
pp. 57-63
Author(s):  
Serhiy Korolko ◽  
Bohdan Seredyuk
Keyword(s):  
Crack Resistance ◽  
High Strength Concrete ◽  
High Speed ◽  
Impact Resistance ◽  
High Strength ◽  
Chemical Additives ◽  
Ultrafine Fibers ◽  
Strength Concrete ◽  
Technical Performance ◽  
Increased Strength

The article considers modern perspectives and directions of using fast – hardening high – strength concretes for protection against striking factors of action of different types of weapons. It is shown that the use of concrete materials in weapons and military equipment is one of the important components of defense structures and protective fortifications during hostilities as platoons and bases, and structures for the protection of civilians. The possibility of obtaining such concretes for the creation of special purpose fortifications is shown. Developed concrete structures have increased strength and impact resistance to high-speed impact. Due to the reinforcement of the concrete structure with mineral and chemical additives and ultrafine fibers, high rates of early strength, viscosity, crack resistance and impact resistance are achieved. The paper presents the main indicators of water consumption, strength and impact resistance of high-strength concrete. The results of the experimental study of samples of the destroyed concrete elements are presented and the corresponding conclusions concerning the use of various types of fibers for reinforcement of such concretes and increase of their crack resistance by basalt fibers are made. It is shown that a high-strength concrete with high construction and technical performance can be successfully used to create protective fortifications and fortifications for special purposes.

The Federal Outlook for High Strength Concrete Bridges

PCI Journal ◽  
1993 ◽  
Vol 38 (3) ◽  
pp. 20-33 ◽  
Author(s):  
Susan N. Lane ◽  
Walter Podolny
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Concrete Bridges ◽  
Strength Concrete

scholarly journals Field Performance of Open-Ended Prestressed High-Strength Concrete Pipe Piles Jacked into Clay

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4216 ◽  
Author(s):  
Hai-Lei Kou ◽  
Wen-Zhou Diao ◽  
Tao Liu ◽  
Dan-Liang Yang ◽  
Suksun Horpibulsuk
Keyword(s):  
Bearing Capacity ◽  
Static Loading ◽  
High Strength Concrete ◽  
Field Tests ◽  
Field Performance ◽  
High Strength ◽  
Loading Test ◽  
Strength Concrete ◽  
Axial Forces ◽  
Static Loading Test

The behavior of open-ended pipe piles is different from that of closed-ended pipe piles due to the soil plugging effect. In this study, a series of field tests were conducted to investigate the behavior of open-ended prestressed high-strength concrete (PHC) pipe piles installed into clay. Two open-ended PHC pipe piles were instrumented with Fiber Bragg Grating (FBG) sensors and jacked into clay for subsequent static loading tests. Soil plug length of the test piles was continuously measured during installation, allowing for calculation of the incremental filling ratio. The recorded data in static loading test were reported and analyzed. The distribution of residual forces after installation and the effect on the bearing capacity were also discussed in detail. The test piles were observed to be in partially plugged condition during installation. The measured ultimate shaft resistance and total resistance of the test piles were 639 and 1180 kN, respectively. The residual forces locked in the test piles after installation significantly affected the evaluation of the axial forces, and thus the shaft and end resistances. It tended to underestimate the end resistances and overestimate the shaft resistances if the residual forces were not considered in the loading test. However, the residual forces did not affect the total bearing capacity of open-ended PHC pipe piles in this study.

Experimental Study on the Maximum Allowable Hydration Temperature for 900t Box Girder of High-Speed Railway

2011 ◽  
Vol 90-93 ◽  
pp. 964-968
Author(s):  
Xue Min Li ◽  
Er Yu Zhu ◽  
Yong Zheng Zhou ◽  
Yue Hong Qin
Keyword(s):  
Experimental Study ◽  
High Strength Concrete ◽  
High Speed ◽  
High Strength ◽  
Maximum Temperature ◽  
Railway Bridge ◽  
Box Girder ◽  
High Speed Railway ◽  
Technical Guide ◽  
Allowable Temperature

Due to the usage of high-strength concrete, excessive hydration heat is generated in the whole span box girder of high-speed railway. The maximum allowable temperature should not exceed 60°C according to the Technical Guide on Railway Bridge Construction of Passenger Dedicated Line. However, according to the field measurement and simulation to the maximum temperature of box girder concrete, we find that the maximum hydration temperature of concrete is generally more than 60°C which is the limited value of the specification. The research results show that the limited value of maximum hydration temperature for box girder concrete can be relaxed to 65°C.

Experimental Study on Fatigue Behavior of Low-Strength Concrete Beams

2011 ◽  
Vol 94-96 ◽  
pp. 795-798
Author(s):  
Hong Wei Tang ◽  
Shi Bin Li
Keyword(s):  
Fatigue Life ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
High Strength ◽  
Concrete Bridges ◽  
Rc Beams ◽  
Strength Concrete ◽  
Steel Bars ◽  
Low Strength

Reinforced concrete (RC) structures taking full advantages of concrete and reinforcing steel bars are widely applied in civil engineering. Concrete bridges are subjected to alternate loads as well as static loads, much importance should be attached to their fatigue. Reinforced concrete beams are the elementary members of concrete bridges. Fatigue failure mode and fatigue life prediction of normal or high-strength RC beams were the research focus at home. The fatigue behavior of low-strength RC beams was studied through four-point bending fatigue test in the paper. The test results indicated that all beams fractured for concrete shear failure, which made the fatigue life of low-strength concrete beams drop greatly compared to that of normal or high-strength concrete beams, because the fatigue failure of normal or high-strength concrete beams were caused by the fracture of one or more reinforcing steel bars; the mid-span deflection development of low-strength RC beams had three phases, and the middle phase occupied about 90% of whole fatigue life, also in the second phase the mid-span deflection developed linearly with the increasing of cycle numbers. This research work provides necessary basis for the fatigue life deterioration of low-strength RC beams.

scholarly journals Field Investigation on Hydroabrasion in High-Speed Sediment-Laden Flows at Sediment Bypass Tunnels

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 469 ◽  
Author(s):  
Michelle Müller-Hagmann ◽  
Ismail Albayrak ◽  
Christian Auel ◽  
Robert M. Boes
Keyword(s):  
Sediment Transport ◽  
High Strength Concrete ◽  
High Speed ◽  
Three Dimensional ◽  
High Strength ◽  
Field Investigation ◽  
Secondary Currents ◽  
Strength Concrete ◽  
Open Questions ◽  
Order Of Magnitude

Wear due to sediment particles in fluid flows, also termed ‘hydroabrasion’ or simply ‘abrasion’, is an omnipresent issue at hydraulic structures as well as in bedrock rivers. However, interactions between flow field, particle motion, channel topography, material properties and abrasion have rarely been investigated on a prototype scale, leaving many open questions as to their quantitative interrelations. Therefore, we investigated hydroabrasion in a multi-year field study at two Swiss Sediment Bypass Tunnels (SBTs). Abrasion depths of various invert materials, hydraulics and sediment transport conditions were determined and used to compute the abrasion coefficients kv of different abrasion models for high-strength concrete and granite. The results reveal that these models are useful to estimate spatially averaged abrasion rates. The kv‑value is about one order of magnitude higher for granite than for high-strength concrete, hence, using material-specific abrasion coefficients enhances the prediction accuracy. Three-dimensional flow structures, i.e., secondary currents occurring both, in the straight and curved sections of the tunnels cause incision channels, while also longitudinally undulating abrasion patterns were observed. Furthermore, hydroabrasion concentrated along joints and protruding edges. The maximum abrasion depths were roughly twice the mean abrasion depths, irrespective of hydraulics, sediment transport conditions and invert material.

Study on Strength Development of High Strength Concrete Containing Alccofine and Fly-Ash

2012 ◽  
Vol 2 (3) ◽  
pp. 102-104 ◽  
Author(s):  
Suthar Sunil B ◽  
◽  
Dr. (Smt.) B. K. Shah Dr. (Smt.) B. K. Shah
Keyword(s):  
Fly Ash ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Development ◽  
Strength Concrete
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