Durability of concrete containing chloride-based accelerating admixtures

1990 ◽  
Vol 17 (1) ◽  
pp. 102-112
Author(s):  
T. Rezansoff ◽  
D. Stott

The influence of CaCl2 or a chloride-based accelerating admixture on the freeze–thaw resistance of concrete was evaluated. Three air entrained mix designs were investigated using ASTM C666-84, Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing. All mix designs were similar, using cement contents of 340–357 kg/m3 of concrete, except for the addition of either 2% calcium chloride or 2% High Early Pozzolith, while no accelerating admixture was added to the control mix. The entire test program was repeated four times with water-to-cement ratio of 0.46 and three times with the ratio of 0.43. For the Pozzolith-accelerated concrete, half the samples were coated with boiled linseed oil in all seven series. For the control (unaccelerated) concrete, half the samples were coated with boiled linseed oil in one series for each water-to-cement ratio. Performance was monitored using the dynamic modulus of elasticity as obtained from transverse resonant frequency measurements. Weight loss of the specimens was also measured. Only the control samples (no accelerators) showed sufficient durability to satisfy the standard of maintaining at least 60% of the original dynamic modulus after 300 cycles of alternate freezing and thawing. Sealing with linseed oil showed inconsistent improvement in the durability in the various test series when defined in terms of the dynamic modulus; however, weight losses were the lowest of all categories and surface scaling was minimal. Key words: concrete, durability, freeze–thaw testing, calcium chloride, admixtures, sealants, air void system.


2014 ◽  
Vol 887-888 ◽  
pp. 814-818
Author(s):  
Li Xue Wang ◽  
Xiao Ting Shan ◽  
Yu Qing Zhang ◽  
Chun Sheng Li ◽  
Zai Xing Wang ◽  
...  

In order to research the changes of concrete properties in freeze-thaw environment, five concrete samples with water-cement ratio respectively equal to 0.60, 0.65, 0.70, 0.75 and 0.80 were tested in freeze-thaw environment according to GB/T50082-2009 concrete rapid freeze-thaw cycles test method. Five samples were carried out 0, 25, 50, 75, 100 times faster freeze-thaw cycles test. With the increasing number of freeze-thaw cycles, the concrete relative dynamic modulus of elasticity loss rises, the compressive strength drops, and the carbonation depth increases. The greater the water-cement ratio of concrete specimens with freeze-thaw cycles, the greater the degree of damage increases.



2010 ◽  
Vol 452-453 ◽  
pp. 657-660
Author(s):  
Ji Ze Mao ◽  
Zong Min Liu ◽  
Koichi Ayuta ◽  
Wan Jie Yin

Freeze-thaw damage is one of the most representative damages in concrete durability. In this study, rapid freezing and thawing tests were conducted to investigate the freeze-thaw resistance and analyze the correlation of the evaluation indexes of lightweight aggregate concrete with different water-cement ratios. The high correlation was confirmed between the length change and relative dynamic modulus of elasticity of lightweight aggregate concrete. The relative dynamic modulus of elasticity decreased with the increase of concrete length. However, the correlation was different according to the water-cement ratio values of lightweight aggregate concrete. The higher water-cement ratios, the lower expansion values of lightweight aggregate concrete when the relative dynamic modulus of elasticity decreased to the same degree under freezing and thawing action.



2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage,this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.



2013 ◽  
Vol 838-841 ◽  
pp. 1801-1805 ◽  
Author(s):  
Li Juan Kong ◽  
Qing Chao Meng ◽  
Yuan Bo Du

Influence of aggregate types on the impermeability and frost-resistance of concrete with different water/cement ratios were investigated, as well as the pore structure and hydrates of the ITZ. The results show that, concrete prepared with a high water/cement ratio and using granite aggregate, presents the highest values of chloride diffusion coefficient and the lowest numbers of freeze-thaw cycles. Whereas concrete prepared with a low water/cement ratio and using limestone aggregate, obtains the similar durability results. The limestone aggregate with a rough surface and higher water absorption, has a tight bonding with the cement paste. However, the granite and basalt aggregate that formed by magma eruption, have higher activity. The XRD results demonstrate that more clinkers participate in the hydration of cement, therefore, resulting in a denser ITZ. In order to improve the concrete durability, the basalt aggregate both with higher activity and rough surface is consider optimal.



2011 ◽  
Vol 25 (31) ◽  
pp. 4307-4310 ◽  
Author(s):  
TAKESHI WATANABE ◽  
YUKI FUJIWARA ◽  
CHIKANORI HASHIMOTO ◽  
KEISUKE ISHIMARU

Self-healing effect is widely known in concrete. It was reported that concrete with fly ash has self healing effect against freezing and thawing damage. Fly ash is one of the popular admixtures as a waste material from coal fired power plant. In this study, main purpose is to evaluate self healing effect of fly ash concrete by ultrasonic test method. In experiment, fly ash replaced 5 and 15 % of unit sand content. To damage fly ash concrete specimens, one of the freezing and thawing test produced by our laboratory were performed. After the test, the fly-ash concrete specimens are cured by water and performed ultrasonic test. In the ultrasonic test, wave forms are detected and wave velocity and ratio of relative dynamic modulus of elasticity are calculated. It is widely known that wave velocity of damaged concrete is slower than sound concrete and dynamic modulus is used for evaluate of damage. As a result, it is recognized that these fly-ash concrete specimens has self healing effect. In addition, in order to investigate curing effect of concrete against freezing and thawing damage, ultrasonic test method is powerful method of nondestructive test.



1991 ◽  
Vol 18 (4) ◽  
pp. 581-589 ◽  
Author(s):  
Michel Pigeon ◽  
Marcel Langlois

There is some controversy about freezing resistance of concrete containing superplasticizers. It has been quite convincingly demonstrated that, in some cases, such admixtures can significantly alter air-void systems in concrete. Some researchers believe, however, that concrete with superplasticizers can resist frost even when the air-void spacing factor is higher than the usual limit of 200 μm. The freeze–thaw cycle resistance tests described in this paper show that with the two types of concrete tested (a plain concrete with a water/cement ratio of 0.50 and a concrete with the same water/cement ratio but containing silica fume), the critical air-void spacing factor value is not significantly affected by the presence of a superplasticizer. When regular concrete is to be exposed to freeze–thaw conditions, the air-void system should meet the usual standards even when a superplasticizer is present. Key words: concrete, freezing and thawing, durability, superplasticizer, spacing factor, silica fume, water–cement ratio. [Journal translation]



2009 ◽  
Vol 405-406 ◽  
pp. 315-321 ◽  
Author(s):  
Yong Ge ◽  
Wen Cui Yang ◽  
Jie Yuan ◽  
Bao Sheng Zhang ◽  
Ai Ling Xiong

The frost resistance of concrete subjected to 3.5% NaCl solution, 5%, 7%, and 10% Na2SO4 solution and seawater were investigated by quick freeze-thaw test. There were two criteria, the relative dynamic modulus of elasticity (RDME) and the mass of scaling, for evaluating the frost resistance of concrete. The results showed that scaling was the main characteristic of deterioration when concrete subjected to freeze-thaw cycles in 3.5% NaCl solution and seawater, whereas RDME had little change. When freezing and thawing in Na2SO4 solution, concrete failed because of internal damage and surfaces of lower strength concrete specimens appeared local swelling and scaling before failure. Concentration of Na2SO4 solution had influence on frost resistance of concrete: deterioration of concrete in 5% or 7% Na2SO4 solution was severe but slower when the concentration reached to 10%. Entraining air into concrete was the best method to improve the durability of concrete subjected to freeze-thaw cycles in all solutions.



1993 ◽  
Vol 20 (5) ◽  
pp. 844-854 ◽  
Author(s):  
J. Wright ◽  
Z. Shen ◽  
S. Rizkalla

Sealers are used to enhance concrete durability through their ability to prevent moisture penetration and chloride intrusion, and, consequently, improve the freeze–thaw performance of the concrete and prevent corrosion of the steel reinforcement, respectively. This paper summarizes the results of three years of comprehensive field and laboratory investigations, undertaken at The University of Manitoba, to study the effectiveness of boiled linseed oil and mineral spirits in comparison to a silane and a siloxane sealer. The field investigation examined the performance of the sealers applied to the concrete pavements of a city street, a provincial highway, and an airport apron in Winnipeg, Manitoba. The laboratory investigation included sealer penetration, salt-water absorption and vapour transmission, abrasion, chloride ion intrusion, surface scaling resistance, and rapid freeze–thaw cycling. Test results of the field and laboratory investigation indicated that boiled linseed oil and mineral spirits was the most effective sealer at reducing chloride ion intrusion. It was found that boiled linseed oil and mineral spirits was comparable to siloxane and much more effective than the silane at reducing salt-water absorption. The results also indicated that boiled linseed oil and mineral spirits was most effective at reducing surface scaling and remained effective when subjected to salt-water absorption after abrasion. Key words: concrete sealers, linseed oil, silane, siloxane, absorption, scaling, chloride intrusion.



2021 ◽  
Author(s):  
Chehong Tsang ◽  
Medhat H. Shehata ◽  
Abdurrahmaan Lotfy

The lack of a standard test method for evaluating the resistance of pervious concrete to cycles of freezing and thawing in the presence of deicing salts is the motive behind this study. Different sample size and geometry, cycle duration, and level of submersion in brine solutions were investigated to achieve an optimized test method. The optimized test method was able to produce different levels of damage when different types of deicing salts were used. The optimized duration of one cycle was found to be 24 h with twelve hours of freezing at −18 °C and twelve hours of thawing at +21 °C, with the bottom 10 mm of the sample submerged in the brine solution. Cylinder samples with a diameter of 100 mm and height of 150 mm were used and found to produce similar results to 150 mm-cubes. Based on the obtained results a mass loss of 3%–5% is proposed as a failure criterion of cylindrical samples. For the materials and within the cycles of freezing/thawing investigated here, the deicers that caused the most damage were NaCl, CaCl2 and urea, followed by MgCl2, potassium acetate, sodium acetate and calcium-magnesium acetate. More testing is needed to validate the effects of different deicers under long term exposures and different temperature ranges.



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