Shrinkage and creep strains of concrete exposed to low relative humidity and high temperature environments

Testing and Analysis of Early Age Stress-Strain Development of Concrete Overlay for Reactor In-Situ Decommissioning

ASME 2011 Pressure Vessels and Piping Conference: Volume 5 ◽

10.1115/pvp2011-57902 ◽

2011 ◽

Author(s):

Hector N. Guerrero ◽

Christine A. Langton ◽

Michael L. Restivo

Keyword(s):

Tensile Strength ◽

Relative Humidity ◽

Concrete Slab ◽

Moisture Distribution ◽

Early Age ◽

Concrete Overlays ◽

Shrinkage And Creep ◽

Differential Shrinkage ◽

Creep Strains

Non-uniform moisture distribution during early age drying and curing of protective concrete overlays for Savannah River Site reactors decommissioned in-situ were expected to result in differential shrinkage that lead to tensile stresses and possible cracking. The goal was to not exceed the concrete tensile strength of 2.8 MPa or compressive strength of 23.8 MPa. An experimental study was performed on the development of shrinkage and creep strains in concrete slab specimens embedded with strain gages and relative humidity sensors at controlled ambient temperature and relative humidity conditions. The experimental data was used to verify the validity of available physics-based methods and code calculations to predict early age shrinkage and creep strains, respectively. Data on the expansive effect of a shrinkage compensating admixture based on CaO was also obtained. Prediction of the surface stress in the test specimen suggests that without the shrinkage compensating admixture, the tensile strength would be slightly exceeded. However with the admixture, the combined effects of shrinkage, creep and expansion due to the admixture is predicted to result in all compressive stresses within the full scale slab, eliminating the possibility of cracking.

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Cultivation of gerbera irrigated with treated domestic effluents

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/s1415-43662010000600003 ◽

2010 ◽

Vol 14 (6) ◽

pp. 582-588 ◽

Cited By ~ 3

Author(s):

Lisânea M. O. Damasceno ◽

Aderson S. de Andrade Júnior ◽

Hans R. Gheyi

Keyword(s):

High Temperature ◽

Experimental Design ◽

Relative Humidity ◽

Plant Development ◽

Leaf Growth ◽

Treated Wastewater ◽

Nutritional Requirements ◽

Randomized Experimental Design ◽

Growth Production ◽

Domestic Effluents

This paper evaluates the nutritional impact on growth, production and quality variables of gerbera crop when fertigated with treated domestic effluents. An experiment was carried out in greenhouse at the Embrapa Meio-Norte in Teresina, in the State of Piauí, Brazil, from July to October 2007. A completely randomized experimental design with five treatments and five replications was adopted. The treatments investigated were T1 - 100% of water and nutritional requirements of crop were met with chemical fertigation (N e K2 O); T2 - 25% volume of water through fertigation and 75% treated wastewater effluents (TWE); T3: 50% volume of water through fertigation and 50% TWE; T4: 75% volume of water with fertigation and 25% TWE; and T5 - 100% volume of water supplied through TWE. Leaf growth and plant development were favored by the application of 50% fertigation and 50% TWE (T3). As for commercial requirements, the best results for number of flowers were obtained with T4. However, concerning quality, T2 produced flowers in July and August with longer stems, but in the months of September and October, no treatment achieved this standard due to high temperature and low relative humidity of the air in the region.

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Influence of weather parameters on alternaria leaf blight severity of makhana under the agro-climate of Koshi region of Bihar

Journal of Agrometeorology ◽

10.54386/jam.v23i1.88 ◽

2021 ◽

Vol 23 (1) ◽

pp. 54-59

Author(s):

SANTOSH KUMAR ◽

MD. NADEEM AKHTAR ◽

SANTOSH KUMAR ◽

MAHESH KUMAR ◽

TRIBHUWAN KUMAR

Keyword(s):

High Temperature ◽

Relative Humidity ◽

Disease Severity ◽

Infection Process ◽

Leaf Blight ◽

Alternaria Leaf Blight ◽

Weather Parameters ◽

Maximum Temperatures ◽

Blight Disease ◽

Cent Disease

Weather parameters play a pivotal role in the infection process and spread of pathogen. It also influences the expression of susceptibility/resistance of the host plant during post-infection phases. Therefore, an experiment was conducted for two consecutive cropping seasons (2018 &2019) to study the influence of weather parameters such as temperature, humidity, rainfall and wind direction on the emergence of alternaria leaf blight of makhana in Koshi region of Bihar. Maximum per cent disease severity of alternarialeaf blightwas observed during the peak monsoon months (June to August). Highest disease severity of leaf blight (14.80% & 15.7%) was observed in the mid June during crop season, 2018 and 2019. High temperature (36.9oC & 38.1oC), and relative humidity (94% & 96.4%) of both the year 2018 and 2019 were found correlated with higher severity to alternaria leaf blight. Similarly average HTR values (3.1) were also found correlated with the average high temperature and relative humidity of both years (2018 and 2019) in terms of severity of leaf blight disease. Maximum temperatures, relative humidity and rainfall exhibited strong positive linear relationship and influenced the occurrence of alternaria leaf blight disease significantly. We also developed a geo-phytopathological model for the prediction of alternaria leaf blight disease of makhana on the basis of congenial mean temperature and relative humidity.

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Effects of High Temperature and Relative Humidity on Mold Content and Quality of Stored Popcorn†

Journal of Food Protection ◽

10.4315/0362-028x-58.9.1018 ◽

1995 ◽

Vol 58 (9) ◽

pp. 1018-1022 ◽

Cited By ~ 4

Author(s):

SARATH K. KATTA ◽

LLOYD B. BULLERMAN

Keyword(s):

High Temperature ◽

Relative Humidity ◽

Storage Time ◽

Gradual Increase ◽

Mold Growth ◽

Internal Mold ◽

Aspergillus Glaucus ◽

Plastic Bag ◽

Open Container

White and yellow popcorn were stored in different containers at high temperature (35°C) and high relative humidity (85%) conditions for 3 months. Gradual decreases in popping volumes with the lengthening of storage time were observed in both white and yellow popcorn. Internal mold infection was quite low in both white (5.7%) and yellow (3.0%) popcorn at the beginning of storage tests. Few differences were found in total infection levels up to 60 days of storage, except that the Aspergillus glaucus group became established in place of field fungi. A gradual increase in mold infection levels was then observed during the remaining 30 days of storage. Visible mold growth was also observed on the tips of some kernels by the end of storage studies. Internal mold infection in white popcorn stored in an open container was lower (18.3%) than white popcorn stored in a closed plastic bag (75.0%) and closed plastic jar (85.3%), whereas the internal mold infection in yellow popcorn stored in an open container was higher (23.3%) than yellow popcorn stored in a closed plastic bag (6.3%) and closed plastic jar (2.6%). The A. glaucus group were the predominant molds found at the end of storage tests. The ability of toxigenic molds to invade the popcorn was determined using a dry spore inoculum. None of the inoculated molds, which included Aspergillus flavus, Penicillium martensii, and Penicillium viridicatum, were able to invade the popcorn during storage. However, the A. glaucus group predominated at the end of storage tests in the inoculated samples.

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EFFECT OF ENVIRONMENT ON BROMOBUTYL RUBBER–STEEL ADHESION

Rubber Chemistry and Technology ◽

10.5254/rct.19.80455 ◽

2019 ◽

Vol 93 (2) ◽

pp. 429-444 ◽

Cited By ~ 2

Author(s):

Essi Sarlin ◽

Ari Rosling ◽

Mari Honkanen ◽

Mari Lindgren ◽

Mira Juutilainen ◽

...

Keyword(s):

Sulfuric Acid ◽

High Temperature ◽

Relative Humidity ◽

Environmental Factors ◽

Adhesive Layer ◽

Metal Structure ◽

Adhesive System ◽

Metal Interface ◽

Weakest Link ◽

Industry Sectors

ABSTRACT Optimizing the maintenance cycles of rubber-lined components is of great importance. Especially for the industry sectors operating under demanding conditions, challenges in the lifetime evaluation of rubber linings may cause apparent premature failures. Thus, understanding the effect of environmental factors on the performance and durability of rubber linings, as well as on the weakest links of the structure in certain environments, is essential. The performances of bromobutyl rubber and rubber–steel interfaces after exposure to different environments, namely, high temperature (95 °C), moisture (95% relative humidity and immersion), and sulfuric acid (solution with 75 g/L of acid) were investigated. The weakest link of the rubber–metal structure and, consequently, the location of the fracture were mostly within the adhesive layer or at the primer–metal interface. However, the most degraded component of the adhesive system depends on the aging environments.

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Creep Properties of Steels Utilized in High-Pressure and High-Temperature Superheater and Steam Pipe Practice. Part I: Carbon Steels

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1944_151_016_02 ◽

1944 ◽

Vol 151 (1) ◽

pp. 54-62 ◽

Cited By ~ 8

Author(s):

H. J. Tapsell

Keyword(s):

High Pressure ◽

High Temperature ◽

Carbon Steels ◽

Creep Properties ◽

Molybdenum Steel ◽

Steam Pipe ◽

Steam Pipes ◽

Sufficient Precision ◽

Creep Strains

This report deals with the creep properties of carbon steels used in superheater headers, superheater tubes, and steam pipes for service at temperatures up to about 480 deg. C. The object of the investigation was to obtain data for the estimation of the stress-temperature relationships for specific creep strains of 0·1–0·5 per cent to occur in 100,000 hours, and these have been obtained with sufficient precision to warrant their acceptance for practical purposes. Similar components in molybdenum steel are under investigation.

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Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Materials ◽

10.3390/ma13071572 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1572 ◽

Cited By ~ 1

Author(s):

Mingnian Wang ◽

Yunpeng Hu ◽

Cheng Jiang ◽

Yicheng Wang ◽

Dagang Liu ◽

...

Keyword(s):

High Temperature ◽

Relative Humidity ◽

Mechanical Characteristics ◽

Coupling Effect ◽

Peak Stress ◽

Curing Temperature ◽

Peak Strain ◽

Humidity Effect ◽

Grouting Material ◽

Study Results

The cement-based grouting materials used for practical purposes in high-geothermal tunnels are inevitably affected by humidity and high temperature, leading to the deterioration of mechanical properties. Based on the characteristics of changing high temperatures and two typical conditions of hot-humid and hot-dry environments in high-geothermal tunnels, many mechanical strength tests were carried out on the grouting material cured under different environmental conditions. The study results indicated that high temperature and low relative humidity were unfavorable to the development of mechanical characteristics of grouting material, but the coupling effect of two factors could improve the strength at early ages and reduce the degradation of long-term strength. As the curing temperature exceeded 56.3 °C, the humidity effect on strength played a more important role in recovering the strength of grouting material damaged by high temperature. Temperature had more significant impact on the relative peak stress while the relative humidity had greater influence on the relative peak strain. A calculation compressive constitutive model was prospered, which considering both temperature and relative humidity. The study results may provide much valuable experimental data and theoretical supporting for the design of compression constitutive of cement-based grouting material in high-geothermal tunnel.

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