scholarly journals EXPERIMENTAL STUDY ON TENSILE DEFORMATION AND CRACKING CRITERIA OF CONCRETE FOR THE EVALUATION OF RESISTANCE OF CONCRETE TO DRYING SHRINKAGE CRACK

2003 ◽  
pp. 135-148 ◽  
Author(s):  
Yusuke AOKI ◽  
Takumi SHIMOMURA
Keyword(s):  
Experimental Study ◽  
Tensile Deformation ◽  
Drying Shrinkage ◽  
Shrinkage Crack

A Numerical and Experimental Study of Cavitation in a Hot Tensile Axisymmetric Testpiece

2005 ◽  
Vol 40 (6) ◽  
pp. 571-586 ◽  
Author(s):  
Y Liu ◽  
J Lin ◽  
T. A Dean ◽  
D. C. J Farrugia
Keyword(s):  
Experimental Study ◽  
Flow Stress ◽  
Grain Boundary ◽  
Thermal Gradient ◽  
Tensile Testing ◽  
Tensile Deformation ◽  
Strain Rates ◽  
Test Results ◽  
Integrated Technique ◽  
Hot Tensile Deformation

During axisymmetric hot tensile testing, necking normally takes place due to the thermal gradient and the accumulation of microdamage. This paper introduces an integrated technique to predict the damage and necking evolution behaviour. Firstly, a set of multiaxial mechanism-based unified viscoplastic-damage constitutive equations is presented. This equation set, which models the evolution of grain boundary (intragranular) and plasticity-induced (intergranular) damage, is determined for a free-cutting steel tested over a range of temperatures and strain rates on a Gleeble thermomechanical simulator. This model has been implemented using the CREEP subroutine of the commercial finite element (FE) solver ABAQUS. Numerical procedures to simulate axisymmetric hot tensile deformation are developed with consideration of the thermal gradient along the axis of the tensile testpiece. FE simulations are carried out to reproduce the necking phenomenon and the evolution of plasticity-induced and grain boundary damage. The simulated results have been validated with experimental tensile test results. The effects of necking and its associated stress state on flow stress and ductility are investigated. The flow stress and ductility data obtained from a Gleeble material simulator under various hot deformation conditions have also been numerically studied.

EXPERIMENTAL STUDY ON DURABILITY OF ROOM TEMPERATURE CURING UFC MORTAR

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Haruka Murakami ◽  
Hiromi Fujiwara ◽  
Masanori Maruoka ◽  
Takahumi Watanabe ◽  
Koji Satori
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
High Performance ◽  
Room Temperature ◽  
Bending Strength ◽  
High Performance Concrete ◽  
Drying Shrinkage ◽  
Concrete Repair ◽  
Repair Materials ◽  
Low Salt

In recent years, as structures become higher, larger, and more durable concrete whose compressive strength of the concrete is 150 N/mm 2 or more have been put to practical use. It is for this reason that it is necessary to develop strengthening materials with equal or better performance. Furthermore, the development of high-performance concrete repair materials is carried out because demand to seismic strengthening and repair increases. In this study, considering these circumstances, it was conducted an experimental study with the aim of developing a repair material using room temperature curing UFC (R-UFC). A binder composition preparation of the R-UFC has excellent fluidity under pressure. It was achieved that high-grade thixotropy, high compressive strength, and high bending strength. It can also be sprayed continuously because of its high thixtoropy. It was confirmed that the sprayed thickness was reached to 20mm by one work. Durability of this R-UFC was investigated and it was confirmed the high sulfate resistance, small drying shrinkage and low salt permeability.

scholarly journals Effects of Sand/Fly Ash and the Water/Solid Ratio on the Mechanical Properties of Engineered Geopolymer Composite and Mix Design Optimization

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 333
Author(s):  
Muhammad Zahid ◽  
Nasir Shafiq
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Response Surface ◽  
Drying Shrinkage ◽  
Sand Fly ◽  
Significance Level ◽  
Solid Ratio ◽  
Geopolymer Matrix ◽  
Two Parameters ◽  
Rsm Technique

This paper presents the results of an experimental study that investigated the effects of two parameters: sand/fly ash (S/FA) ratio and water to geopolymer-solid (W/GS) ratio on the engineered geopolymer composite. The trial mix designs were optimized using the response surface method. These parameters influence the properties of the fresh and hardened geopolymer matrix, such as slump flow, compressive strength, flexural strength, elastic modulus, flexural toughness, ductility index and drying shrinkage. The optimizing process was conducted by developing statistical models using the response surface methodology (RSM) technique. The developed models were statistically validated and could be used to determine the desired response of engineered geopolymer composite (EGC) with a significance level of more than 95%. In this study, the optimized values of the S/FA ratio and W/GS ratio were obtained as 0.341701 and 0.225184, respectively. To validate the optimized S/FA ratio and W/GS ratio, an experimental study was performed, and a difference of less than 5% was found between predicted and experimental results.

scholarly journals An experimental study on production of high strength non-shrink grout containing fly ash

2021 ◽  
Vol 72 (4) ◽  
pp. 477-485
Author(s):  
Chi Dang Thuy
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Drying Shrinkage ◽  
High Strength ◽  
Fine Aggregate ◽  
Expansive Agent ◽  
Chemical Admixture ◽  
The University ◽  
The Given

Cement-based grouts are widely used thanks to its outstanding features such as high workability, non-separation, non-bleeding, easy to fulfill small gaps with complex shapes. This paper descrcibes the first phase of a series of laboratory experiments that examined the ability of production of self - levelling mortar at the University of Transport and Communications. The Portland cement-based grout incorporated superplasticizer, fly ash, fine aggregate, water along with expansion agent to match as closed as possible the given high strength non-shrink grout. The experimental study focused on the performance of non-shrink grouts regarding the flowability, expansion and bleeding, strengths and drying shrinkage of the test grout mixtures. The high range water reducer (HRWR) at dosage of 1% by weight of cement was used as a flowability modifying chemical admixture to prevent water segregation and leads to an increase in compressive strength. The parameter tests consist of water-cement ratios, and fixed dosages of superplasticizer and expansive agent. To examine the flowability of grout mortars, the flow cone test was applied. The flow cone test result indicated that there were three proportional of grouts that can meet the requirement of fluidity. The compressive strength of specimens was tested according to ASTM C349-14. It was concluded that the compositions of grouts at a water-cement ratio of from 0.29 to 0.33 have compressive strengths greater than 60 MPa. The tested specimens using the expansive agent with the dosage recommended by the manufacturer meet the non-shrinkage requirement of a grout. The experimental results have demonstrated the ability of production of high strength non-shrink grouts.

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