Study of Frost Resistance of 50 Years Concrete Exposed to Saline Areas

2013 ◽  
Vol 275-277 ◽  
pp. 1341-1346
Author(s):  
De Cheng Zhang ◽  
Yan Ping Lv ◽  
Zheng Mao Ye
Keyword(s):  
Frost Resistance ◽  
High Performance ◽  
Large Temperature ◽  
Freezing And Thawing ◽  
The North ◽  
Single Side ◽  
Concrete Mechanical Properties ◽  
Saline Area ◽  
Design Requirements ◽  
Freezing And Thawing Cycles

The Hong Run petrochemical oil depot is located in a saline area in the north of Weifang.This area is severe cold in winter and has large temperature span throughout a year. Due to the area's rigorous environmental conditions, concrete with 50 years durability and strength grade of C40 was fabricated with the ordinary Portland cement, high performance superfine mineral powder and high performance pumping agent. Tests using the onsite concrete samples show that concrete mechanical properties meet the design requirements. After 300 freezing and thawing cycles including accelerated freezing thawing method and single-side freezing thawing method, the quality loss rate and relative dynamic modulus both comply with the design requirements. This suggests that the sample concrete has excellent frost resistance ability.

scholarly journals EXPERIENCE OF APPLICATION HIGH PERFORMANCE CEMENT COMPOSITES FOR CREATING DURABLE SCULPTURAL ELEMENTS

2017 ◽  
Vol 3 ◽  
pp. 286
Author(s):  
Genadijs Sahmenko ◽  
Sandis Aispurs ◽  
Aleksandrs Korjakins
Keyword(s):  
Water Absorption ◽  
High Performance ◽  
Cement Composite ◽  
Cement Composites ◽  
Freezing And Thawing ◽  
Initial Water ◽  
Good Potential ◽  
Freezing And Thawing Cycles ◽  
Material Ductility ◽  
And Control

Traditionally, sculptural and decorative elements of building facades are created from mortar mixes based on lime, gypsum or Portland cement. Generally these materials have porous and permeable structure, which determines their accelerated degradation, especially in the aggressive environment of modern cities. High performance cement composites (HPCC) have been considered for production and restoration of sculptural elements in historical buildings. For this purpose, fine-graded, multi-component and highly workable mixes were elaborated. Mix compositions were modified with micro-fillers, plasticizing and stabilizing admixtures, as well as fibers to improve material ductility and control shrinkage cracking. Basic mechanical properties and durability (such as water absorption, frost resistance) were determined and two types of HPCC were compared (>50 MPa: HPCC and >120 MPa: UHPCC). It has been confirmed that cement composite mixes are characterized by self-consolidating effect, high compressive strength, extremely high resistance versus freezing and thawing cycles and low water absorption. Surface quality was evaluated and initial water absorption (tube tests) were performed for laboratory samples and real sculptural elements after 5 years of exploitation. The results confirmed good potential for using HPCC for creating more attractive and durable architectural shapes and façade elements compared to elements made using traditional cement and lime mortar.

scholarly journals Experimental Study on Freezing and Thawing Cycles of Shrinkage-Compensating Concrete with Double Expansive Agents

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1850
Author(s):  
Jinjun Guo ◽  
Ting Guo ◽  
Shiwei Zhang ◽  
Yan Lu
Keyword(s):  
Frost Resistance ◽  
Large Scale ◽  
Mass Loss Rate ◽  
Test Results ◽  
Freezing And Thawing ◽  
Expansive Agent ◽  
Hydraulic Concrete ◽  
Mix Proportion ◽  
Three Stages ◽  
Freezing And Thawing Cycles

The freezing and thawing of construction concrete is becoming an increasingly important structural challenge. In this study, a shrinkage-compensating concrete based on a double expansive admixture was developed and its frost resistance was assessed through rapid freezing and thawing cycling. The frost resistance of the concrete was derived through the measurement and calculation of the relative dynamic modulus of elasticity (RDME) and the mass loss rate (MLR), and the freezing- and thawing-cycle microstructures and products of concretes with different expansive agents were analyzed using scanning electron microscopy (SEM). It was shown that changes in the properties of the concrete under freezing and thawing could be divided into three stages: slow-damage stage, fast-damage stage, and stable stage. Compared to concrete without an expansive agent, a single-expansive-agent concrete demonstrated excellent frost resistance during the slow-damage stage, but the frost resistance rapidly decreased during the fast-damage age. After 150 cycles (the stable-damage stage), the concrete with a U-type expansive agent (UEA): MgO expansive agent (MEA) mix proportion of 2:1 had the best frost resistance, with RDME and MLR values 17.35% higher and 25.1% lower respectively, than that of an expansive-agent-free concrete. These test results provide a basis for the study of frost resistance in large-scale hydraulic concrete structures.

scholarly journals Durability of Hydrophobic/Icephobic Coatings in Protection of Lightweight Concrete with Waste Aggregate

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 101
Author(s):  
Danuta Barnat-Hunek ◽  
Jacek Góra ◽  
Marcin K. Widomski
Keyword(s):  
Frost Resistance ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
High Porosity ◽  
Freezing And Thawing ◽  
Adhesive Properties ◽  
Surface Protection ◽  
High Durability ◽  
Before And After ◽  
Freezing And Thawing Cycles

The aim of the research presented in this paper is to evaluate the feasibility of using hydrophobic agents based on organosilicon compounds for surface protection of lightweight concrete modified with waste polystyrene. The experimental part pertains to the physical and mechanical properties of polystyrene-modified lightweight concrete. The concrete samples were prepared with the following ingredients: CEM I 42.5 R cement, recycled polystyrene (0–2 mm), quartz sand (0–2 mm), coarse river aggregate (2–16 mm), and water. Silane and tetramethoxysilane were employed for surface hydrophobization. Concrete with 20% polystyrene exhibits high porosity (25.22%), which is related to an increase in absorptivity (14.75%) compared to the reference concrete. The hydrophobized concrete is characterized by the lowest surface free energy (SFE) value, which is 7 or 11 times lower than the value of reference concrete, depending on the agents. The test on the contact angle (CA) was performed before and after the frost-resistance test (F–T test). Lower SFE translates into lower adhesive properties, higher resistance of the material to the infiltration of water and corrosive compounds, e.g., salts, and higher resistance to freezing and thawing cycles. Silane and tetramethoxysilane coating raised frost resistance by 54–58% compared to the reference samples. This agent reduced absorptivity by 30%. Recycled polystyrene can be successfully used to produce lightweight concrete (LC) with high durability provided by hydrophobic/icephobic coatings.

scholarly journals Freezing and thawing resistance of internally cured high performance concrete

2018 ◽  
Vol 162 ◽  
pp. 02011
Author(s):  
Muthana Saadi ◽  
Tareq al-Attar ◽  
Shatha Hasan
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Internal Curing ◽  
Fine Aggregate ◽  
Freezing And Thawing ◽  
Cast Concrete ◽  
Curing Method ◽  
Compressive And Flexural Strengths ◽  
Limestone Dust ◽  
Freezing And Thawing Cycles

The behavior of internally cured high performance concrete, HPC, exposed to freezing and thawing cycles, was investigated. Two saturated curing agents, Limestone dust and powder of Porcelanite rock, were used to facilitate internal curing for concrete. These agents were used as partial replacements of fine aggregate in two volumetric percentages, 20 and 30 percent. The cast concrete specimens were separated in two groups according to curing method: water-cured and sealed (only internally-cured) specimens. The concrete specimens were subjected to three exposure systems, F0: without freezing and thawing, and F1 and F2: with 50 and 100 cycles of freezing and thawing, respectively. The freezing and thawing test was done as stipulated by the ASTM C666. The conducted tests for each exposure were: compressive and flexural strengths. The results revealed that internal curing does not enhance the concrete resistance to freezing and thawing cycles. Using saturated agents has increased the moisture content of concrete and makes it more vulnerable to frost action deterioration. Sealed specimens for all investigated mixes showed lower reductions in strength than water-cured ones. The lesser water content of these mixes may be the reason for that behavior.

Corrosion Resistance of 50 Years Concrete Exposed to Saline Areas

2014 ◽  
Vol 584-586 ◽  
pp. 1165-1171
Author(s):  
De Cheng Zhang ◽  
Yan Ping Lv ◽  
Sheng Li Fan ◽  
Min Ouyang ◽  
Xiao Lei Xu
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
High Performance ◽  
Chloride Ion ◽  
Chloride Penetration ◽  
Expansion Rate ◽  
Electric Transport ◽  
The North ◽  
Saline Area ◽  
Astm C1202

The Hong Run petrochemical oil depot is located in a saline area in the north of Weifang, where the contents of chloride and sulfate in this area are very high. Due to the rigorous environmental conditions, concrete with 50 years durability and C40 strength grade was prepared. A kind of corrosion resistance concrete with high performance superfine mineral powder and high performance pumping agent was developed to adapt to the conditions in saline areas. The chloride-penetration resistance ability was investigated by the test of chloride ion rapid electric transport (ASTM C1202). The concrete compressive strength and mortar expansion rate under continuous immersion in four different corrosion solutions was studied. The results showed that the chloride-penetration grade is very low. The compressive strength is high and the mortar expansion rate lower than 0.1%.

Dependence of Relative Decreasing in Strength by Rate of Strain for the New Rapid Method for Determination of Concrete Frost Resistance

2015 ◽  
Vol 725-726 ◽  
pp. 505-510
Author(s):  
Olga Pertseva ◽  
Sergey Nikolskiy
Keyword(s):  
Tensile Strength ◽  
Rapid Method ◽  
Frost Resistance ◽  
New Method ◽  
Basic Method ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Freezing And Thawing Cycles ◽  
Non Destructive

The task of the project is obtaining the dependence between the relative decreasing of strength and rate of strain and substantiation of the new method for determination of concrete frost resistance. It has been analytically proved that using concrete’s rate of strain ε as a measure of damage, instead of decreasing of tensile strength R, increases freeze-thaw resistance’s accuracy of estimation a lot under otherwise equal conditions by the time of freeze-thaw cycling. Also it has been experimentally shown that ratio of relative decreasing R to ε in direction, perpendicular to compression, is assumed to be independent on values R and ε for a given concrete and on the ways of achieving them during mechanical or freeze-thaw cycling. To determine the dependence δR/R by ε (z) 8 specimens were tested by non-destructive method (RU 2 490 631) and two baths of 50 specimens by basic method (thermo cycling). Results of the non-destructive method are different from results by basic method for 6,3%. Dependence of relative decreasing in strength by rate of strain is near to linear and, therefore, value of z is constant. Taking this into account patented methods for estimation of concrete’s freeze-thaw resistance as per values R and ε received after freezing and thawing cycles of some specimens and their postlimenary failure by linear compression was substantiated.

Study of Frost Resistance on Air-Entrained Concrete in Sulfated Medium

2006 ◽  
Vol 302-303 ◽  
pp. 125-130 ◽  
Author(s):  
Ge Yong ◽  
Yuan Jie ◽  
Wen Cui Yang ◽  
Bao Sheng Zhang
Keyword(s):  
Fresh Water ◽  
Frost Resistance ◽  
Plain Concrete ◽  
Sulfate Solution ◽  
Test Results ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Freezing And Thawing Cycles ◽  
Air Entrained Concrete ◽  
Sodium Solution

Frost resistance of plain concrete and air-entrained concrete subjected to freeze-thaw cycles in fresh water and 5 % and 7 % sodium sulfate solution are investigated in this paper. The test results show that the frost resistance of concrete is different in the different medium. The properties of concrete frozen in 5 % and 7 % sodium solution are different from that in fresh water, and entraining air into concrete properly can increase the frost resistance significantly whether in fresh water or in sulfate solution. Higher strength concrete could resist the degradation of freezing and thawing cycles in water, but some of them failed suddenly in midspan of specimens under the sulfate solution.

scholarly journals Effect of Hydrophobic Treatments on Improving the Salt Frost Resistance of Concrete

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5361
Author(s):  
Guo Li ◽  
Chunhua Fan ◽  
Yajun Lv ◽  
Fujun Fan
Keyword(s):  
Water Absorption ◽  
Frost Resistance ◽  
Contact Angles ◽  
Water Repellent ◽  
Freezing And Thawing ◽  
Ordinary Water ◽  
Salt Scaling ◽  
Mass Losses ◽  
Hydrophobic Treatment ◽  
Freezing And Thawing Cycles

Hydrophobic treatment is an important method to improve the waterproof properties of concrete. To evaluate the effectiveness of hydrophobic treatments on improving the salt frost resistance of concrete, two representative commercial ordinary water repellent agents of silane and organosilicone emulsion were selected, and concrete specimens with three water/cement ratios were fabricated. After the application of repellent agents on concrete surfaces, accelerated saline (5% MgCl2) freeze-thaw cycles were conducted on the specimens. The mass losses and relative dynamic modulus of elasticity (RDME) of concrete were tested periodically. The contact angles and water absorption ratios of concrete with and without hydrophobic treatments were also tested. Results showed that the repellent agents could substantially enhance the hydrophobicity of concrete and greatly reduce its water absorption. Different repellent agents exerted diverse improvements on concrete hydrophobicity. Meanwhile, the repellent agents could improve concrete resistance against salt scaling and RDME losses to a certain degree, and concrete with strong hydrophobicity showed relatively high salt frost resistance. However, the ordinary water repellent agents cannot achieve the same enhancement on salt frost resistance of concrete as that on the water hydrophobicity of concrete. With saline freezing and thawing cycles, the hydrophobic layer formed by the repellent agents on superficial concrete was destroyed gradually. As a result, the salt frost resistance of concrete from the hydrophobic treatments was ultimately lost.

Pharmacokinetics and Tissue Distribution Study of Ferruginol in Wistar Rat by High-performance Liquid Chromatography

2018 ◽  
Vol 15 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Guiyun Cao ◽  
Suqiao Han ◽  
Keke Li ◽  
Li Shen ◽  
Xiaohong Wang ◽  
...  
Keyword(s):  
Tissue Distribution ◽  
Mobile Phase ◽  
High Performance ◽  
Wistar Rat ◽  
Freezing And Thawing ◽  
Promising Candidate ◽  
Distribution Study ◽  
Substance Loss ◽  
Tissue Distribution Study ◽  
The Brain

Background: Ferruginol (FRGN) exhibits a broad range of pharmacological properties which make it a promising candidate for chemoprevention. However, little is known about its absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. Methods: A rapid, sensitive and specific HPLC-DAD method was established to quantify FRGN in the plasma and tissues of Wistar rats. After extraction of FRGN with ethyl acetate (EtOAc), chromatographic separation was performed on a YMC ODS C18 column (250 × 4.6 mm I.D., 5 µm) with a mobile phase consisting of methanol-water (92:8, v/v) at a flow rate of 0.9 mL/min. Detection was conducted with a wavelength of 273 nm at 25 °C. Results: The calibration curves for FRGN were linear in the concentration range of 0.5-20 µg/mL for plasma, 0.5-10 µg/mL for heart, liver, spleen, lung, kidney, stomach, intestine, brain and muscle. After three cycles of freezing and thawing, the concentration variations were within ± 7% of nominal concentrations, indicating no significant substance loss during repeated thawing and freezing. The assay was applied to pharmacokinetic and tissue distribution study in rats. Results suggested that lung, heart, liver, spleen and kidney were the major distribution tissues of FRGN in rats, and FRGN could permeate the blood-brain barrier to distribute in the brain of rats. Conclusion: The information provided by this research is very useful for gaining knowledge of the pharmacokinetic process and tissue distribution of FRGN.

Bestimmung der Dauerhaftigkeit von Hochleistungsbeton mit Hilfe des CDF-Tests / Determination of the durability of high performance concrete by means of CDF-test

1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth
Keyword(s):  
Frost Resistance ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Factors Influencing

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.

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