Suggestion for the Simplified Pullout test of Normal Concrete Strength

2017 ◽  
Vol 33 (4) ◽  
pp. 29-36
Author(s):  
Hune-Bum Ko ◽  
Eun-Ho Cha ◽  
Kang-Hwan Oh
Keyword(s):  
Concrete Strength ◽  
Pullout Test ◽  
Normal Concrete

Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu
Keyword(s):  
Normal State ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Normal Concrete ◽  
Strength Criteria ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

scholarly journals Studi Kuat Tekan Beton Speedcrete Dengan Zat Additive Naphthalene Berdasarkan Variasi Umur

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Syifa Fauziah ◽  
Anisah Anisah ◽  
Sittati Musalamah
Keyword(s):  
Compressive Strength ◽  
Test Object ◽  
Treatment Process ◽  
Concrete Strength ◽  
Test Machine ◽  
Water Age ◽  
Normal Concrete ◽  
Compressive Strength Of Concrete ◽  
Normal Strength ◽  
Additive Materials

This research aims to determine the maximum compressive strength value of concrete speedcrete using naphthalene additive additive at each test age and compare with normal concrete 28 days. This research used cylindrical test object with diameter 15 cm and height 30 cm. Speedcrete concrete does not undergo the treatment process while the normal concrete test object through the treatment process. Testing compressive strength of concrete speedcrete using Crushing Test Machine tool. In this research the compressive strength was produced by using superplasticizer type naphthalene and compared with normal concrete without using additive. The target quality plan is fc '35 MPa with the use of additive dose of 1.7% of the weight of cement. The results of this research showed an increase in the value of compressive strength of concrete speedcrete with aadditive materials added naphthalene increased with increasing age of concrete. The results showed that the compressive strength of concrete speedcrete with naphthalene additive materials of 12 hours, 18 hours, 28 hours and 48 hours was 0.5 MPa, 17,81 MPa, 31,14 MPa and 45,77 MPa. Normal strength concrete strength with the addition of 20% water age 28 days that is equal to 54.76 MPa.

scholarly journals Effect of Improper Curing on the Properties of Normal Strength Concrete

2018 ◽  
Vol 8 (6) ◽  
pp. 3536-3540
Author(s):  
R. P. Memon ◽  
A. R. M. Sam ◽  
A. Z. Awang ◽  
U. I. Memon
Keyword(s):  
Cement Content ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Controlled Environment ◽  
Normal Strength Concrete ◽  
Normal Concrete ◽  
Normal Strength

In real applications, 28 days are regarded as proper curing time for concrete. There is a self-evident need to minimize the duration of curing days. For this purpose, this research investigates 1 to 7 days of curing and compares it with concrete cured for 28 days. Three grades of normal concrete strength grade 30, grade 35 and grade 40 were made. After curing, two exposure conditions were applied to the concrete, inside laboratory-controlled environment and outside environment. Results indicate that slump increases with cement content in DOE method at constant water content. The concrete density in all grades reduces when the concrete is subject to inside exposure in comparison with outside exposure. Water loss from concrete reduces with increase in curing days in all concrete grades. Compression strength of all concrete grades increases with increase in curing days. For the uniformity of concrete, ultrasonic pulse velocity indicated that with an increase in curing days, concrete becomes denser and a bit void. Results showed that an increase in curing days also improves the surface quality of concrete. The significance point noticed is that there was not much difference in the concrete properties between 7 days of curing and 28 days of curing in all grades.

Effect of Curing Regime on Compressive Strength of Concrete Containing Malaysian Laterite Aggregate

2012 ◽  
Vol 626 ◽  
pp. 839-843 ◽  
Author(s):  
Norul Wahida Kamaruzaman ◽  
Khairunisa Muthusamy
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Curing Process ◽  
Normal Concrete ◽  
Strength Performance ◽  
Compressive Strength Test ◽  
Water Curing ◽  
Compressive Strength Of Concrete ◽  
Curing Regime ◽  
Curing Age

Concrete subjected to improper curing process would exhibit poor strength performance due to incomplete hydration process. This research investigate the effect of curing regime towards compressive strength of concrete containing Malaysian laterite aggregate (MLA) as partial coarse aggregate replacement. Concrete specimens produced using a range of laterite aggregate replacement from 0 to 50% were placed in different curing regime namely water curing, natural weather curing and air curing until the testing date. Specimens were subjected to compressive strength test in accordance to BS EN 12390 at 60 days. The results show strength of all specimens except the air cured samples increase as the curing age become longer. It was found that water curing is the most suitable for better performance of laterite concrete. The presence of water throughout the curing process is very much crucial for laterite concrete strength developement compared to normal concrete.

scholarly journals Research on the Bond Behavior of Preplaced Aggregate Concrete-Filled Steel Tube Columns

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 300 ◽  
Author(s):  
Jing Lv ◽  
Tianhua Zhou ◽  
Qiang Du ◽  
Kunlun Li ◽  
Liangwei Jin
Keyword(s):  
Bond Strength ◽  
Concrete Strength ◽  
Peak Load ◽  
Steel Tube ◽  
Bond Stress ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Concrete Filled Steel Tube ◽  
Bond Behavior ◽  
The Difference

In order to investigate the bond behavior of preplaced aggregate concrete-filled steel tube (CFT-PAC) columns and the difference of bond behavior between CFT-PAC columns and normal concrete-filled steel tube (CFT-NC) columns, a total of 11 columns were prepared and the push-out tests were conducted. The experimental parameters included the type of concrete (preplaced aggregate concrete and normal concrete), concrete strength (C40, C50 and C60), cross-section dimension (D = 219 mm, 299 mm and 351 mm) and the thickness of steel tube (t = 6 mm and 8 mm). The results indicated that the CTF-PAC columns had a similar load-slip curves with CFT-NC columns. The bond stresses of the CFT-PAC columns were higher than that of the PAC-NC columns at the same concrete strength. Increasing compressive strength of PAC increased the critical bond strength and bond strength of CFT-PAC columns. With an increase of the L/D ratio, both of the slip corresponding to peak load and bond strength of CFT-PAC columns exhibited an increasing trend. A rise in the D/t ratio led to a decrease in the bond stress of CFT-PAC columns and an increase in slip corresponding to the peak load of CFT-PAC columns. The proposed bond stress–slip relationship model considerably matched the bond stress–slip relationship of CFT-PAC columns.

Prédiction des résistances du ciment au laitier durcissant sous une temperature variable

2001 ◽  
Vol 28 (4) ◽  
pp. 555-561 ◽  
Author(s):  
Bougara Abdelkader ◽  
Ezziane Karim ◽  
Kadri Abdelkader
Keyword(s):  
Construction Industry ◽  
Concrete Strength ◽  
Normal Concrete ◽  
Activation Temperature ◽  
Equivalent Time ◽  
Treatment Prediction ◽  
Different Temperatures ◽  
Curing Methods ◽  
Temperature Variable ◽  
Mineral Additives

The prediction of concrete strength has become a major concern that is forcing the construction industry to look closely at determining the appropriate time when to strip the form work or to apply prestress forces to new concrete. Normal concrete has different constitutions and can be subjected to different curing methods depending on the means available. Its characteristics are defined by the presence of mineral additives used to improve its efficiency. This has led us to establish a work plan to predict the strength of slag concrete, tested at different temperatures, from the data obtained from some control specimens of normal concrete, made only from clinker and subjected to a constant temperature of 20°C. The slag material was obtained from El-Hadjar (Algeria).Key words: slag, activation, temperature, finesse, thermal treatment, prediction, equivalent time, mortar, compression, cement, additives.

scholarly journals Tests on sea sand concrete-filled stainless steel tubular stub columns

2018 ◽  
Author(s):  
Feiyu Liao ◽  
Chao Hou ◽  
W. J. Zhang ◽  
J. Ren
Keyword(s):  
Stainless Steel ◽  
Concrete Strength ◽  
High Strength ◽  
Normal Concrete ◽  
River Sand ◽  
Concrete Core ◽  
Cross Sectional ◽  
Composite Columns ◽  
Sea Sand ◽  
Stub Columns

This paper presents a series of tests on sea sand concrete-filled stainless steel tubular (SSCFST) stub columns under axial compression, where the main test parameters include type of fine aggregates (river sand, desalted sea sand and sea sand), steel ratio, and concrete strength. The failure mode, axial load versus axial shorten response, cross-sectional strength of the SSCFST specimens are investigated and compared with those of traditional composite columns with normal concrete. The confinement effect between stainless tube and the sea sand concrete is also evaluated. High strength and good ductility was observed for the tested SSCFST stub columns. In general, when being used as the concrete core in a composite column, differences of confinement behaviour between sea sand concrete and normal concrete are not significant, indicating the potential adoption of SSCFST columns in practice.

Experimental Study on Mechanical Behavior of Concrete Loading along Path (Constant Stress, Constant Strain, Increasing Strain)

2012 ◽  
Vol 238 ◽  
pp. 91-95
Author(s):  
Zhe Wang ◽  
Jing Li ◽  
Ren Jie Shang
Keyword(s):  
Experimental Study ◽  
Principal Stress ◽  
Concrete Strength ◽  
Test System ◽  
Normal Concrete ◽  
Peak Point ◽  
Linear Relationships ◽  
Minimum Principal Stress ◽  
Two Stages ◽  
The Relationship

Triaxial compressive experiments were performed with normal concrete by using the large triaxial test system. The loading process was divided into two stages: (1) Under the condition of keeping the three axial stresses equivalent, the compressive stress was increased to a specified value p, which was maintained for a period of time; (2) The strain in y direction was increased monotonously while the stress in x direction and the strain in z direction both remained constant. In this paper, the study on the experiments indicates: the minimum principal stress significantly influences the strength of concrete, i.e., the greater the minimum principal stress is, the greater the concrete strength is; the stress in y direction where the strain stayed constant is the middle principal stress; the constant strain influences the relationship between σ2 and σ1, they reach the peak values at the same time and approximate to linear relationships in much parts of their descending stage, curvature only appears at their ends; When ε13>8, each relationship curve of τ13-γ13 gradually becomes horizontal；Below a line AB in figure of coordinate system εx, εy the curves of εx-εy approximately parallel to each other; If the minimum principal stress is 15MPa or 20MPa, After εkk reaches the peak point, the volume gradually becomes stable after a transient decrease stage.

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