Effect of Supplementary Curing after Steam-Curing on Performance of Concrete

2016 ◽  
Vol 852 ◽  
pp. 1376-1382
Author(s):  
Xiao Li ◽  
Wan Yang Niu
Keyword(s):  
Water Content ◽  
Hydration Products ◽  
Steam Curing ◽  
Carbonation Depth ◽  
Test Environment ◽  
Average Temperature ◽  
Daily Average ◽  
Saturated Water ◽  
Daily Average Temperature ◽  
Saturated Water Content

When the low strength grade of steam-curing concrete is produced, the temperature which the concrete leaves steam-curing kiln is about 20°C commonly. The temperature difference is too large between the environmental temperature and the temperature which the concrete leaves steam-curing kiln when the daily average temperature drops to 10°C. Because the steam-curing concrete is cooled rapidly, a large of crack will be produced in concrete and the internal structure of concrete will be damaged normally. Then the performance of concrete will be influenced badly. In order to improve the negative effect on concrete by steam curing, the different supplementary curing is used after steam curing. The C30 concrete is made in this research. The daily average temperature is 5°C~10°C and the minimum temperature is-6°C during the test. After the concrete is formed, it is placed in 20°C environment for 2h first. Then the concrete is heated to 55°C in 2h and maintained for 8h in the steam-curing kiln. In the end, the concrete is cooled to 20°C in 3h. After steam curing, the standard curing and covering by wet fabric or film outside are used separately for concrete. The supplementary curing time is 1d, 2d, 3d and 4d. Then the concrete is placed in natural environment to 28d. The microstructure of hydration products are observed by electron microscope. The density of concrete is analyzed by the result of the 28d saturated water content, softening factor and 28d rapid carbonation depth. The mechanical properties of concrete are researched by the result of the 28d strength. When the concrete adopts standard curing or covering by film after steam-curing, the saturated water content and 28d rapid carbonation depth of the concrete will reduce, but the softening factor and 28d strength of the concrete will increase with the time. The performance of concrete which adopts covering by wet fabric after steam-curing is worse than that adopting standard curing. At the same time, the saturated water content and softening factor of concrete change little. Covering by wet fabric is worse than no covering or similar. In the test environment, the performance of the steam-curing concrete with each supplementary curing is worse than that of the concrete with standard curing. The standard curing is the best supplementary curing in this test. But covering by film is a worthy supplementary curing from economy and practicability. Covering by film for 4d, the 28d strength of steam-curing concrete is 87 percent of that of the concrete with standard curing and exceeds Design grade. Its saturated water content is 1.50% and softening factor is 0.932. Its rapid carbonation depth is close to that of the concrete with standard curing and its microstructure of hydration products is preferable.

Prediction of soil saturated water content using evolutionary polynomial regression (EPR)

2013 ◽  
Vol 60 (8) ◽  
pp. 1155-1172 ◽  
Author(s):  
Shokufeh Salehi Khoshkroudi ◽  
Mohammad Ali Gholami Sefidkouhi ◽  
Mirkhalegh Ziatabar Ahmadi ◽  
Meysam Ramezani
Keyword(s):  
Water Content ◽  
Polynomial Regression ◽  
Evolutionary Polynomial Regression ◽  
Saturated Water ◽  
Saturated Water Content

Addition of suitably-designed zwitterions improves the saturated water content of hydrophobic ionic liquids

2012 ◽  
Vol 48 (91) ◽  
pp. 11220 ◽  
Author(s):  
Yoritsugu Ito ◽  
Yuki Kohno ◽  
Nobuhumi Nakamura ◽  
Hiroyuki Ohno
Keyword(s):  
Ionic Liquids ◽  
Water Content ◽  
Saturated Water ◽  
Saturated Water Content ◽  
Hydrophobic Ionic Liquids

Modeling the Daily Average Temperature

2012 ◽  
pp. 87-164
Author(s):  
Antonis K. Alexandridis ◽  
Achilleas D. Zapranis
Keyword(s):  
Average Temperature ◽  
Daily Average ◽  
Daily Average Temperature

scholarly journals The Saturated Water Content of Liquid Propane in Equilibrium with the sII Hydrate

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6295
Author(s):  
Kayode I. Adeniyi ◽  
Connor E. Deering ◽  
Robert A. Marriott
Keyword(s):  
Water Content ◽  
Relative Difference ◽  
Dew Point ◽  
Helmholtz Equations ◽  
Liquid Propane ◽  
Saturated Water ◽  
Three Phase ◽  
Reference Quality ◽  
Saturated Water Content ◽  
Good Agreement

In order to prevent solids from forming during the transportation and handling of liquid propane, C3H8(l), the fluid is dehydrated to a level below the water dew point concentration for the coldest operating temperature. Thus, accurate calculation of the saturation water content for C3H8 is important to determine the designed allowable concentration in liquid C3H8. In this work, we measured the water content of liquid C3H8 in the presence of the structure II hydrate from p = 1.081 to 40.064 MPa and T = 241.95 to 276.11 K using a tunable diode absorption spectroscopy technique. The water content results were modelled using the reference quality reduced Helmholtz equations and the Sloan et al. model for the non-hydrate and hydrate phases, respectively. Calculations show a good agreement (an average difference of less than 12 ppm) when compared to our measurements. Furthermore, the model was also used for calculating the dissociation temperatures for three phase loci, where a relative difference greater than 5 K was observed compared to the literature, hence our previously model reported by Adeniyi et al. is recommended for three phase loci calculations.

scholarly journals Outdoor temperature and survival benefit of empiric potassium in users of furosemide in US Medicaid enrollees: a cohort study

BMJ Open ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. e023809
Author(s):  
Young Hee Nam ◽  
Warren B Bilker ◽  
Charles E Leonard ◽  
Michelle L Bell ◽  
Sean Hennessy
Keyword(s):  
Cohort Study ◽  
Survival Benefit ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Total N ◽  
Average Temperature ◽  
Daily Average ◽  
Daily Average Temperature ◽  
All Cause Mortality

ObjectiveHeat is associated with elevated all-cause mortality, and furosemide-induced potassium depletion might be worsened by heat-induced sweating. Because empiric potassium is associated with a marked survival benefit in users of furosemide at a dose of ≥40 mg/day, we hypothesised that this empiric potassium’s survival benefit would increase with higher temperature (≥24°C).DesignCohort study.SettingOutpatient setting, captured by Medicaid claims, supplemented with Medicare claims for dual enrollees, from 5 US states from 1999 to 2010, linked to meteorological data.Population/ParticipantsFurosemide (≥40 mg/day) initiators among adults continuously enrolled in Medicaid for at least 1 year prior to cohort entry (defined as the day following the dispensing day of each individual’s first observed furosemide prescription).ExposureInteraction between: (1) empiric potassium, dispensed the day of or the day following the dispensing of the initial furosemide prescription, and (2) daily average temperature and daily maximum temperature, examined separately.OutcomeAll-cause mortality.ResultsIn 1:1 propensity score matched cohorts (total n=211 878) that included 89 335 person-years and 9007 deaths, all-cause mortality rates per 1000 person-years were 96.0 (95% CI 93.2 to 98.9) and 105.8 (95% CI 102.8 to 108.9) for potassium users and non-users, respectively. The adjusted OR of all-cause mortality for potassium use declined (ie, its apparent protective effect increased) as temperature increased, from a daily average temperature of about 28°C and a daily maximum temperature of about 31°C. This relationship was not statistically significant with daily average temperature, but was statistically significant with daily maximum temperature (p values for the interaction of potassium with daily maximum temperature and daily maximum temperature squared were 0.031 and 0.028, respectively).ConclusionsThe results suggest that empiric potassium’s survival benefit among furosemide (≥40 mg/day) initiators may increase as daily maximum temperature increases. If this relationship is real, use of empiric potassium in Medicaid enrollees initiating furosemide might be particularly important on hot days.

scholarly journals The Role of Phosphorus Slag in Steam-Cured Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Jin Liu ◽  
Dongmin Wang
Keyword(s):  
Pore Structure ◽  
Water Content ◽  
Hydration Heat ◽  
Curing Temperature ◽  
Hydration Products ◽  
Hydration Degree ◽  
Steam Curing ◽  
Chloride Permeability ◽  
Early Hydration

Steam curing is an effective method to increase the hydration degree of binder containing phosphorus slag. The role of phosphorus slag in steam-cured concrete was investigated by determining the hydration heat, hydration products, nonevaporable water content, pore structure of paste, and the compressive strength and chloride ion permeability of concrete. The results show that elevated steam curing temperature does not lead to new crystalline hydration products of the composite binder containing phosphorus slag. Elevating steam curing temperature enhances the early hydration heat and nonevaporable water content of the binder containing phosphorus slag more significantly than increasing steam curing time, and it also results in higher late-age hydration degree and finer pore structure. For steam-cured concrete containing phosphorus slag, elevating curing temperature from 60°C to 80°C tends to decrease the late-age strength and increase the chloride permeability. However, at constant curing temperature of 60°C, the steam-cured concrete containing phosphorus slag can achieve satisfied demoulding strength and late-age strength and chloride permeability by extending the steam curing duration.

scholarly journals Estimation of daily average temperature using multisource spatial data in data sparse regions of Central Asia

2013 ◽  
Vol 7 (1) ◽  
pp. 073478 ◽  
Author(s):  
Mingyong Cai ◽  
Shengtian Yang ◽  
Changsen Zhao ◽  
Hongjuan Zeng ◽  
Qiuwen Zhou
Keyword(s):  
Central Asia ◽  
Spatial Data ◽  
Average Temperature ◽  
Daily Average ◽  
Daily Average Temperature

Influence of leaf surface wax and leaf area to water content ratio on cuticular transpiration in western conifers, U.S.A.

1990 ◽  
Vol 20 (9) ◽  
pp. 1306-1311 ◽  
Author(s):  
Julian L. Hadley ◽  
William K. Smith
Keyword(s):  
Water Content ◽  
Leaf Surface ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Forest Trees ◽  
Cuticular Transpiration ◽  
Saturated Water ◽  
Surface Wax ◽  
Saturated Water Content ◽  
Leaf Surface Wax

High cuticular water loss, desiccation, and leaf mortality during winter in conifers at alpine timberline represent especially dramatic examples of the ecophysiological importance of cuticular transpiration. However, little research has been conducted on the winter water relations of forest trees, even though recent evidence suggests a potentially high leaf mortality due, at least in part, to winter desiccation. Two factors that could have important influences on cuticular transpiration, leaf surface wax and the ratio of leaf area (A) to saturated water content (Mw), were compared for six conifer species common to the central Rocky Mountains, United States. Leaves were collected from forest trees at the end of winter (May) to compare the amount of leaf surface wax, cuticular conductance to water vapor (gc), and leaf water content. Decreases in relative leaf water content were much more linearly related to transpiration per unit saturated water content than either gc or A/Mw, separately. Only A/Mw appeared correlated with the rate of cuticular transpiration. Also, linear increases in gc occurred with increasing leaf water content. Estimated desiccation resistance during winter corresponded closely to the degree of drought tolerance characterized previously for each species based only on summer growth conditions. Thus, winter desiccation resistance may be an important, yet under-emphasized, ecological factor influencing conifer distribution patterns.

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