General Analytical Model for Nominal Shear Stress of Type 2 Normal- and High-Strength Concrete Beam-Column Joints

2004 ◽  
Vol 101 (1) ◽  
Keyword(s):  
Shear Stress ◽  
Analytical Model ◽  
High Strength Concrete ◽  
Concrete Beam ◽  
High Strength ◽  
Strength Concrete

scholarly journals Reduce the Influence of Horizontal and Vertical Cold Joints on the Behavior of High Strength Concrete Beam Casting in Hot Weather by Using Sugar Molasses

2018 ◽  
Vol 7 (4.19) ◽  
pp. 794
Author(s):  
Fatimah Hameed Naser Al-Mamoori ◽  
Ali Hameed Naser Al-Mamoori
Keyword(s):  
High Strength Concrete ◽  
Concrete Beam ◽  
Setting Time ◽  
Weather Condition ◽  
High Strength ◽  
Point Load ◽  
Concrete Element ◽  
Strength Concrete ◽  
Hot Weather ◽  
The Impact

The current research studies the effect of cold joints on the behavior shear and flexure of High Strength Concrete (HSC) beams caused by delayed casting sequence during the hot weather in summer of Iraq.Fresh concrete should be kept alive during the various casting batches for concrete element by re-vibration. However, the over vibration caused loss in homogeneity and it is difficult to keep the workability of concrete during hot weather due to the effect of setting time.To deal with this problem of improper casting sequence, which eventually leads to the formation of cold joints, it will be used sugar waste (named as Sugar Molasses (SM)) is a by-product resulted from refining process of sugar as a delayed agent to increase the setting time in order to prevent early set of concrete due to adverse effects in construction joint of hot weather.In the current study, the first objective aims to investigate some of fresh and hardened mechanical properties of HSC (with high cement content) using SM at percentages of (0, 0.05, 0.1, 0.2, 0.3) % from the weight of cement under the concept of sustainable development. The second objective aims to investigate the location and surface texture effect of horizontal and vertical cold joints on the flexural and shear behavior of beam with/without SM. This objective includes testing of twenty four plain concrete beam of (110×110×650 mm) under two point load; half of them casting without roughing (smooth) the old layer and the other casted after roughed it.SM content of 0.2% of cement weight can improve compressive strength by about 11.2% at 28 days and delay initial setting time by about 4.617 hours (277 minutes). No adverse effect on concrete have been observed at this dosage of SM concentration for the ages of concrete cylinders studied. Delays in the setting of concrete at this dosage of SM content help in reducing the early setting of concrete and therefore reduced the impact of the cold joints formation in concrete beams under Iraqi hot weather condition. The failure load for the beams with SM of smooth and rough vertical joints is in the range between (1.95 - 2.12) and (1.46-1.37); respectively times that of the case of beam without SM. 

Behaviour of reinforced high-strength concrete beam—column joint. Part II: numerical simulation

2004 ◽  
Vol 5 (3) ◽  
pp. 101-112 ◽  
Author(s):  
A. El-Nabawy Atta ◽  
S. El-Din Fahmy Taher ◽  
A.-H. A. Khalil ◽  
S. E. El-Metwally
Keyword(s):  
Numerical Simulation ◽  
High Strength Concrete ◽  
Concrete Beam ◽  
High Strength ◽  
Strength Concrete ◽  
Column Joint

Flexural Performance of BFRP Bar Reinforced High-Strength Concrete Beam

2021 ◽  
pp. 111-120
Author(s):  
Yan Xie ◽  
Kaiyuan Zhuo ◽  
Khuram Rashid ◽  
Jun Deng ◽  
Faji Zhang
Keyword(s):  
High Strength Concrete ◽  
Concrete Beam ◽  
High Strength ◽  
Strength Concrete ◽  
Flexural Performance

Specimen Size and Shape Effects on the Concrete Properties, Thermal Conductivity and Heat Generation from Hydration for Different Concrete Types

2019 ◽  
Vol 16 (10) ◽  
pp. 4072-4091 ◽  
Author(s):  
Ola Adel Qasim
Keyword(s):  
Thermal Conductivity ◽  
Reinforced Concrete ◽  
Heat Generation ◽  
High Strength Concrete ◽  
Concrete Beam ◽  
Concrete Strength ◽  
High Strength ◽  
Strength Concrete ◽  
Concrete Properties ◽  
The Difference

The environmental impact, manufacture and the application of concrete have many influences, some of which are influential and complex. Construction engineers are looking for modern ideas and methods that make the building more efficient in terms of functionality, cost, high strength, reduced overloads and increased efficiency of unlimited geometric shapes. The main factor in the improvement and development of concrete structures rely on the engineering characteristics of the substances. The developments in the construction materials, mix proportions, dimensions, mixing, and conditions (temperature) used to enhance the concrete technology, have important impacts on characteristics of concrete strength and heat development manner. The heat generation from concrete reveals the components of concrete materials and mix balances as well as the innovations in structure and environmental circumstances. This research presented an experimental investigation of the significance of the specimen’s shape and the size of the concrete properties durability, thermal conductivity and heat generation. Cylinders, prisms, and cubes of different sizes and shapes will be used. This research concluded that the effect of molds shape and size decreased when the (strength in compression, splitting tensile strength, flexural strength, and concrete density) increasing, that’s mean for ultra-high-strength concrete the difference is much smaller. The concrete hydration due to heat increases with increasing of the concrete strength and size, and the difference in heat transfer with the increasing of specimen’s size decreasing with increasing of concrete size. It is completely identified that the deformation and intensity of reinforced concrete beams depend on the size of the beam. Effect of concrete types (normal 26 MPa, high 46 MPa, and ultra-high-strength concrete 61 MPa) on the design of reinforced concrete beam was studied with three different depth (170, 155 and 150 mm). Results revealed that high strength and ultra-high-strength concrete was able to substitute for the reduction in beams size with the same strength. For concrete that is high or ultra-high-strength a reduction in the beam depth of about (8.82%) and (11.76%) compared to the normal concrete beam where achieved.

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