scholarly journals A linear test method for determining early-age shrinkage of concrete

2008 ◽  
Vol 60 (10) ◽  
pp. 747-757 ◽  
Author(s):  
M. D. Newlands ◽  
K. A. Paine ◽  
N. A. Vemuri ◽  
R. K. Dhir
Keyword(s):  
Test Method ◽  
Early Age

Dumbbell Test Method for Evaluation of the Early Age Cracking Property of Concrete Material by Stress Risers

2012 ◽  
Vol 503-504 ◽  
pp. 473-476
Author(s):  
Yan Liu ◽  
Zhi Gang Luo ◽  
Jie Cao
Keyword(s):  
Test Method ◽  
Early Age ◽  
Construction Site ◽  
Quick Method ◽  
Concrete Material ◽  
Stress Risers ◽  
Test Technology ◽  
Cracking Performance ◽  
Simulated Test ◽  
Job Site

This article develops one new test technology, dumbbell test method, for evaluation of the early age cracking property of Concrete Material under constraint conditions. Its exercise of stress risers could lead concrete to crack quickly, providing a quick method to evaluate the early age crack performance of concrete material and to perform simulated test at job site conveniently. By this method, the anti-cracking performance of different concrete material can be evaluated quickly in the construction site.

Effect of Fly Ash on the early Age Cracking Performance of Cement Paste

2014 ◽  
Vol 584-586 ◽  
pp. 894-898
Author(s):  
Ping Zhang ◽  
Guan Guo Liu ◽  
Chao Ming Pang ◽  
Bing Du ◽  
Hong Gen Qin
Keyword(s):  
Computed Tomography ◽  
Fly Ash ◽  
Cement Paste ◽  
Test Method ◽  
Early Age ◽  
Cement Ratio ◽  
X Ray ◽  
Cracking Performance ◽  
X Ray Computed ◽  
Ct Test

The X ray computed tomography (X-CT) was applied to test the cracking resistance of cement paste, and the hydration process was monitored to study the effect of fly ash on the early age cracking performance. The results showed that the hydration heat reduced with the increase of fly ash under the same water-cement ratio. Within 24h, the porosity increased with time. The addition of fly ash increased the proportion of large holes and then changed the internal stress state. Using X-CT test method and by comparing the number of cracks, the sample with 20% FA was found to have the most serious cracks, whereas the sample with 30% FA had the best crack resistance.

scholarly journals Study on estimation of creep behaviour of concrete at early age considering temperature effect

2019 ◽  
Vol 289 ◽  
pp. 10010
Author(s):  
Kayo Ohashi ◽  
Jun-ichi Arai ◽  
Toshiaki Mizobuchi
Keyword(s):  
Thermal Stress ◽  
Temperature Effect ◽  
Creep Strain ◽  
Prediction Accuracy ◽  
Creep Behaviour ◽  
Test Method ◽  
Control Measures ◽  
Experimental Result ◽  
Early Age ◽  
And Control

Clarifying the creep behaviour of concrete at early age not only improves the accuracy of temperature stress analysis but also contributes to prediction accuracy and control measures in cracks caused by thermal stress. However, most past researches on creep behaviour were investigated after 28 days. Currently, it is difficult to accurately perceive the creep behaviour of concrete at an early age in the test method of creep which is generally carried out. Therefore, it is necessary to evaluate the creep behaviour of concrete at early age and to establish a convenient test method to estimate the creep behaviour. Therefore, in this study, experiments were carried out for concrete at early age within one week. As the result of the experiments, it was shown that the creep strain is proportional to the load stress of concrete at an early age and the strain of specific creep decreases as the loaded age increases. In addition, based on the experimental results, an estimation equation for creep strain at early age was proposed. Within the scope of this experimental result, it was confirmed that the estimation equation proposed in this study accurately represented the creep behaviour of concrete at early age.

The Research of GGBS’ Influence on the Cracking Resistance of Concrete

2014 ◽  
Vol 919-921 ◽  
pp. 1864-1867
Author(s):  
Yan Liu ◽  
Dao Xun Ma
Keyword(s):  
Test Method ◽  
Early Age ◽  
Cracking Resistance ◽  
Volume Stability ◽  
The Impact

The aim of this paper is to study the impact of GGBS on the early age cracking resistance of concrete. To assess the volume stability of premixed concrete under different dosage of GGBS an innovative cracking test method is adopted, and the causes and effect mechanisms of that are analyzed.

Early Age Cracking Characteristic of Concrete with Compound Admixtures

2013 ◽  
Vol 325-326 ◽  
pp. 71-74
Author(s):  
Yun Feng Li ◽  
Dong Sheng Zhang ◽  
Li Xu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Test Method ◽  
Mineral Admixture ◽  
Early Age ◽  
Furnace Slag

The shrinkage cracking of concrete plays an important role to the accelerated deterioration and shortening the service life of concrete structures. The mineral admixture will be a perfect component of high performance concrete and its utilization will be a valuable resource for recycling. Early age cracking characteristics of concrete with compound admixtures, such as steel slag, blast furnace slag, fly ash, are studied in this paper using plate test method. The better anti-cracking performance of concrete will be realized when blast furnace slag replacing cement at 30%, steel slag and fly ash as the equal mixture components replacing cement at 30%, three kinds of admixtures replacing cement at 30% under the proper proportion.

Air-entrained grouts suitable for post-tensioning

1984 ◽  
Vol 11 (1) ◽  
pp. 92-98
Author(s):  
R. E. Loov ◽  
S. P. Hon ◽  
M. A. Ward
Keyword(s):  
Empirical Test ◽  
Structural Member ◽  
Test Method ◽  
Early Age ◽  
Air Content ◽  
Water To Cement Ratio ◽  
Post Tensioning ◽  
Entrained Air ◽  
Original Water ◽  
Test Bottle

Grouts in post-tensioning ducts can cause cracking of the structural member if the grout freezes at an early age. This laboratory program examines a range of cement–water grouts with differing w/c ratios, air contents, and ages. A new empirical test method employing a test bottle was introduced to study the performance of grouts during early freezing.It was determined using the bottle method and other experimental and analytical procedures that excessive grout dilation during early freezing could be avoided if the entrained air content of the grout exceeded[Formula: see text]where w/c is the original water-to-cement ratio of the grout and M is the fraction of the cement that has hydrated before the grout freezes.

scholarly journals Limestone and Calcined Clay-Based Sustainable Cementitious Materials for 3D Concrete Printing: A Fundamental Study of Extrudability and Early-Age Strength Development

2019 ◽  
Vol 9 (9) ◽  
pp. 1809 ◽  
Author(s):  
Chen ◽  
Li ◽  
Chaves Figueiredo ◽  
Çopuroğlu ◽  
Veer ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Cementitious Materials ◽  
Strength Test ◽  
Test Method ◽  
Strength Development ◽  
Early Age ◽  
Ambient Conditions ◽  
Calcined Clay ◽  
Green Strength

The goal of this study is to investigate the effects of different grades of calcined clay on the extrudability and early-age strength development under ambient conditions. Four mix designs were proposed. Three of them contained high, medium, and low grades of calcined clay, respectively, and one was the reference without calcined clay. In terms of extrudability, an extrusion test method based on the ram extruder was introduced to observe the quality of extruded material filaments, and to determine the extrusion pressure of tested materials at different ages. For evaluating the very early-age strength development, the penetration resistance test, the green strength test, and the ultrasonic pulse velocity test were applied. Furthermore, the mechanical properties of the developed mix designs were determined by the compressive strength test at 1, 7 and 28 days. Finally, the main finding of this study was that increasing the metakaolin content in calcined clay could significantly increase the extrusion pressures and green strength, shorten the initial setting time and enhance the compressive strength at 1, 7, and 28 days.

The Research on the Crack Performance of Airport Pavement Concrete with the Mineral Admixture of Fly Ash

2013 ◽  
Vol 807-809 ◽  
pp. 2699-2702 ◽  
Author(s):  
Yan Liu ◽  
Bin Xiao
Keyword(s):  
Fly Ash ◽  
Test Method ◽  
Mineral Admixture ◽  
Early Age ◽  
Concrete Material ◽  
Volume Stability ◽  
Airport Pavement ◽  
Pavement Concrete

This paper studies the influence of fly ash with different dosage and grades on the crack performance of airport pavement concrete. In order to test airport pavement concrete material accurately and quickly, Dumbbell Test Method was introduced in its early-age from pouring. Dumbbell Test Method is able to evaluate the effect of fly ash with different grades and dosage on volume stability of airport pavement concrete. This paper also studied the mechanism of the influence of fly ash crack performance of airport pavement concrete.

Sign in / Sign up

Export Citation Format

Share Document