scholarly journals Experimental study on fiber mortar strength at early age under temperature difference

2019 ◽  
Vol 264 ◽  
pp. 02005
Author(s):  
Yan Zhang ◽  
Ning Li
Keyword(s):  
High Temperature ◽  
Temperature Difference ◽  
Concrete Structure ◽  
Early Age ◽  
Experimental Basis ◽  
Cement Concrete ◽  
Influence Of Temperature ◽  
Mortar Strength ◽  
Strength Change ◽  
Strength Difference

The condition of high temperature is easy to destroy the concrete structure of tunnels. Many temperature difference conditions are applied to ordinary mortar and fiber mortar specimens, the early strength values of mortar caused by temperature change were measured. The flexural strength change rules of the specimens were analysed. The influence of temperature difference on different specimens, and the cause of the strength difference and failure of the specimens are studied. It provides experimental basis for improving the service life of high temperature tunnel cement concrete structure.

Influence of High-Temperature Curing on the Properties of the Concrete Containing Ground Iron and Steel Slag

2014 ◽  
Vol 507 ◽  
pp. 337-342
Author(s):  
Meng Yuan Li ◽  
Jin Hu
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Steel Slag ◽  
Curing Temperature ◽  
Early Age ◽  
Cement Concrete ◽  
Chloride Permeability ◽  
Iron And Steel ◽  
Negative Effect ◽  
Curing Condition

The influence of high-temperature curing on the compressive strength and chloride permeability of the concrete containing ground iron and steel slag (GISS) was investigated. Under standard curing condition (20°C), the early-age compressive strength of the concrete with GISS is much lower than that of the pure cement concrete. The activity of GISS is more sensitive to the increase of curing temperature than that of cement. The increase amplitude of early-age strength of the concrete with GISS is much greater than that of the pure cement concrete by increasing curing temperature. Increasing curing temperature tends to decease the late-age strength and enhance the late-age permeability of concrete. The negative effect of increasing curing temperature on the late-age properties of the concrete with GISS is smaller than that of the pure cement concrete.

THE INFLUENCE OF TEMPERATURE AND SOIL MOISTURE ON THE PHYTOTOXICITY OF DICAMBA, PICLORAM, BROMOXYNIL, AND 2,4-D ESTER

1966 ◽  
Vol 46 (6) ◽  
pp. 653-660 ◽  
Author(s):  
H. A. Friesen ◽  
D. A. Dew
Keyword(s):  
Soil Moisture ◽  
High Temperature ◽  
High Light Intensity ◽  
High Light ◽  
Test Plant ◽  
Optimum Growth ◽  
Limited Growth ◽  
Fagopyrum Tataricum ◽  
Influence Of Temperature ◽  
Reduced Activity

Moisture and temperature differentially affected the phytotoxicity of four herbicides to tartary buckwheat, Fagopyrum tataricum (L.) Gaertn., the test plant. The activity of the systemic herbicides 2,4-D, dicamba, and picloram was greatest when conditions of soil moisture and air temperature tended toward optimum growth of the buckwheat. When moisture limited growth the phytotoxicity of these three herbicides was significantly less. Reducing the temperature from the optimum 24°–13 °C to 18°–7 °C did not significantly reduce the activity of these herbicides. Conversely, the phytotoxicity of the contact herbicide bromoxynil was significantly greater at the low rather than the high temperature program. This activity was accentuated when moisture was also made limiting but its effect was less pronounced. High light intensity tended to result in abnormal buckwheat growth and reduced activity of the herbicides.

Effects of heat stress on growth, some blood variables and lipid oxidation in broilers exposed to high temperature at an early age

2000 ◽  
Vol 41 (4) ◽  
pp. 489-493 ◽  
Author(s):  
O. Altan ◽  
A. Altan ◽  
I. Oguz ◽  
A. Pabuçcuoglu ◽  
S. Konyalioglu
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Lipid Oxidation ◽  
Early Age ◽  
Blood Variables

Early-age performance of longitudinal bridge joints made with shrinkage-compensating cement concrete

2019 ◽  
Vol 197 ◽  
pp. 109391 ◽  
Author(s):  
Weizhuo Shi ◽  
Behrouz Shafei ◽  
Zhengyu Liu ◽  
Brent M. Phares
Keyword(s):  
Early Age ◽  
Cement Concrete ◽  
Bridge Joints

Relationship between temperature and sterilizing efficiency of heat treatments of equal duration. Experimental testing with suspensions of spores in milk heated in an ultra-high-temperature sterilizer

1975 ◽  
Vol 42 (3) ◽  
pp. 437-444 ◽  
Author(s):  
J. Hermier ◽  
P. Begue ◽  
O. Cerf
Keyword(s):  
High Temperature ◽  
Heating Temperature ◽  
Experimental Testing ◽  
Bacillus Coagulans ◽  
Efficiency Curve ◽  
Special Effect ◽  
Influence Of Temperature ◽  
Dimensionless Constant ◽  
Image Position ◽  
Ultra High Temperature

SummaryA relationship between temperature and sterilizing efficiency of heat treatment at constant time is described and checked experimentally using spores of Bacillus coagulans 604 in a pilot ultra-high-temperature plant. The relation is:whereN0andNare initial and final concentrations of spores,Tthe temperature (°C),zthe temperature coefficient (°C,z=10/logQ10) andAa dimensionless constant. A special effect of the injection of spores into live steam is observed. The sterilizing efficiency curve can be used in determining the heating temperature for a desired sterilizing efficiency and in predicting the influence of temperature fluctuation on sterilizing efficiency.

scholarly journals Effects of Shrinkage Reducing Agent and Expansive Additive on Plastic Shrinkage of Mortar at Different Temperatures

2018 ◽  
Vol 206 ◽  
pp. 02002
Author(s):  
Sarapon Treesuwan ◽  
Komsan Maleesee ◽  
Shigeyuki Date
Keyword(s):  
High Temperature ◽  
Setting Time ◽  
Reducing Agent ◽  
Early Age ◽  
Initial Setting Time ◽  
Plastic Shrinkage ◽  
Different Temperatures ◽  
Expansive Additive ◽  
Hot Weather ◽  
Shrinkage Reducing Agent

In the construction, it is inevitable to perform plaster work in hot weather which causes the dehydration and rapid shrinkage on the paste during the early age. This research shows the studies of reducing the plastic shrinkage of mortar during the early age with such additives as the Shrinkage Reducing Agent (SRA), the Expansive Additive (EX), and the Fly Ash (FA) in controlled temperatures at 30°C and 40°C, with relative humidity between 60% and 70% according to the ASTM C1579-06 standard, with the strain gauge installed at 0.5 cm.from the surface. The shrinkage rate was measured starting from the Initial Setting Time and every 10 minutes afterwards for 24 hours. The results show that high temperature effects the cracking and how to use different formulas of additive under different circumstances is considerably important. To use only one additive is not sufficient in high temperature. To use the SRA in addition to the EX enhances better expansion than to use only the EX. Moreover, it is recommended to pay close attention in adding large amount of the FA into mortar with the EX and SRA added which extremely enhances the expansion and potential cracking.

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