Long-Term Durability of Cold Weather Concrete : Phase II

Gazi University Journal of …, 2011

This study aims to determine the effect of antifreeze admixture used in the concretes subjected to frost action on the concrete compressive strength. Three groups of concrete samples of C30 class were prepared with antifreeze admixtures by using the mixture of 30% calcium nitrate and 5% hydroxy ethoxy amin (A), calcium nitrate (B), Polyhydroxy amine (C). Concrete samples are put in the freezer in a fresh state 15 min after the mixing. Samples are subjected to frost action in 0,-5,-10,-15 and-20°C degrees for 48 hours. On the concrete samples water cured after 48 hours, compressive strength tests of 28 day are conducted. Consequently, it is seen that with the increase of the set temperature that concrete is cured, compressive strength of concrete is decreased and among all types of antifreezes the maximum decrease is seen between 0 and-5°C while the decrease in compressive strength is relatively less for-10,-15 and-20°C.

Cold Regions Science and Technology, 2016

This study focused on the effect of antifreeze additives on the microstructural changes and physical and mechanical properties of fresh concrete subjected to freezing-thawing cycles produced by cold weather. For this purpose, antifreeze additives, urea and calcium nitrate, were used at the level of 6% by weight of cement dosage and were compared with control samples. After casting, one group of control samples was cured in moist curing conditions for 1 day and then cured in lime-saturated water at 23 ± 1°C for 28 days. Another group of controls, urea and calcium nitrate mixtures, were subjected to freezing-thawing cycles 1, 3, 5, 7, 10, 15 and 28 times. Scanning electron microscopic (SEM) images, ultrasonic pulse velocity (UPV), water absorption and compressive strength tests were conducted. The results showed that the lowest water absorption value after 28 freezing-thawing cycles was 5.8% for the calcium nitrate mixes. The 28-day compressive strength of the control, calcium nitrate and urea mixes subjected to freezing-thawing 28 times was reduced by 72.0%, 27.8% and 52.9% compared to those of the control samples cured in lime-saturated water at 23 ± 1°C for 28 days. The SEM images showed that the samples containing calcium nitrate had a more compact and denser micro-structure compared to urea and the control.

1997

This report presents freeze-thaw durability results of an investigation regarding the application of high performance concrete (HPC) to prestressed bridge girders. This study included a total of 30 concrete mixes and more than 130 specimens, with the following variables: aggregate type: round river gravel, partially-crushed gravel, granite, high-absorption limestone, and low-absorption limestone; cementitious material composition: Type III portland cement only, 20% fly ash, 7.5% silica fume, and combination of 20% fly ash with 7.5% silica fume replacement by weight of cement; and curing condition: heat-cured or seven-day moist-cured. No air-entraining agents were used in the study's initial phase to simulate the production of precast/prestressed bridge girders. Results indicate that it is possible to produce portland cement concrete with high strength and freeze-thaw durability without the use of air-entraining agents. Overall, the moist-cured concrete specimens exhibited better...

2018

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, F 0 : without freezing and thawing, and F 1 and F 2 : 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.

Construction and Building Materials, 1996

There are two basic frost durability problems: internal cracking due to freezing and thawing cycles, and surface scaling, generally due to freezing in the presence of deicer salts. Although there are still parts of the problem which are not perfectly well understood and warrant further investigation, particularly with respect to the differences between laboratory tests and field exposure, the way to make concrete resistant to freezing and thawing cycles is very well known. It is simply to ensure that the hardened concrete has an adequate system of entrained air voids. Field experience as well as laboratory data has shown very conclusively that internal cracking due to frost in properly airentrained concretes is almost non-existent. Scaling due to freezing in the presence of deicer salts is a much more complex problem than internal cracking for many reasons, but probably mainly because it is related to the microstructure of the very surface layer or 'skin' of concrete. Properly airentrained and properly cured well-designed Portland cement field concretes are generally quite resistant to deicer salt scaling, but scaling still sometimes occurs unexpectedly after only a few years. Research in this area is therefore required. The ability of the commonly used deicer salt scaling tests to predict the performance of concrete under normal field exposure conditions must also be particularly investigated. In addition, research is needed to better understand the process of the formation of large air voids in air-entrained concrete, since the dosage of air-entraining admixtures is based on the total volume of air in the mixture, and small dosages that yield an adequate air volume often do not yield an adequate air void spacing factor (and thus adequate frost protection).

Simultaneous measurement on surface scaling and moisture uptake is undertaken. HSC mixes are more prone to internal damage, albeit the high scaling resistance. A bi-linear pattern is noted for mass loss and moisture uptake of HSC mixes. Air-void characteristics is not a major factor in surface scaling of HSC mixes.

Zenodo (CERN European Organization for Nuclear Research), 2023

Concrete is a porous material that allow water to penetrate into it, which will undergo "freeze-thaw cycles" at places which experience large temperature swings, eventually popping the surface of the concrete off. To reduce freeze-thaw damage in cementitious materials, air entraining admixtures (AEAs) have been utilised. But the entrained air gaps weaken and increase the permeability of concrete, rendering it prone to various types of in situ deterioration. Researchers in Colorado incorporated antifreezing polymer molecules into concrete, inspired by animals that survive in subzero temperatures. It is described as a soluble biomimetic antifreeze polymer with Ice Recrystallization Inhibition (IRI) and Dynamic Ice Shaping (DIS) properties that can inhibit ice crystal development damage in concrete and cement paste. In high-pH environments typical of concrete pore solution, the polyethylene glycol-graftpolyvinyl alcohol (PEG-PVA) polymer replicates the explicit IRI and DIS activity of natural ice-binding proteins. It reduces freeze-thaw damage and boosts concrete strength and durability, extending the life of new infrastructure and lowering carbon emissions during its lifetime.

2001

Research on freeze-thaw resistance of concrete in general and on curing and moisture conditions in particular is motivated from an economic and product sustainability point of view. Specifically, it is argued for the importance of considering the effect of curing and test exposure conditions on the moisture uptake and performance during freeze-thaw. Due to the demonstrated importance of moisture conditions on performance, they should be related to those of field service conditions when choosing a test procedure in a particular case. This is vital for adequate testing of newand more sustainable concrete materials.

Cold Regions Science and Technology, 2013

Based on ACI 306R-10, the minimum temperature necessary for maintaining concrete hydration and strength gaining is 5°C. If the weather becomes lower than 5°C, some special measures should be taken in order to prevent decrease in the rate of hydration and to prevent fresh concrete from freezing. Most of the cold weather living countries spend annually plenty of money in order to facilitate concrete placing in the cold weather and to extend the construction season. It has been investigated that the behavior of fresh and hardened concrete contained calcium nitrate at different curing temperatures below freezing temperature of water and compare the results with the both control samples. For this reason, calcium nitrate is used at level of 6% by weight of cement dosage in mixes. After casting, one group of samples was cured in the different deepfreezes at − 5°C, − 10°C, − 15°C, and − 20°C for 7, 14 and 28 days, and then the same samples were cured in water at (23 ± 1.7)°C for 7, 14, and 28 days. Calcium nitrate increased the compressive strength of concrete between 48-964, 50-721, 29-393 and 24-183%, for −5°C, − 10°C, −15°C and − 20°C, respectively, when compared to mixes without antifreeze admixtures. The results showed that it is possible to use calcium nitrate as an antifreeze admixture in concrete technology in cold weather concreting without additional precautions.

Structural Concrete, 2020

This article is aimed at investigating the long-term performance of three original hydrophobic materials, namely, sodium acetate, fluoropolymer, and silicone resin. Their performance was compared with traditional silane when applied to fully dry concrete, fully saturated concrete, and concrete with 2 and 4% moisture content. A recently developed freeze-thaw process, which is based on temperature and humidity variations, was employed in this study to assess the durability of applied materials. The outcomes of the adopted freeze-thaw system were compared with the results obtained from running a conventional freeze-thaw test. Mass change, water absorption, and micro-cracks development of treated concrete were investigated and compared with untreated concrete after completing 6 months of freeze-thaw cycles. Results confirmed the high affinity of the proposed materials to moisture at application time compared with silane. Additionally, it was demonstrated that moisture content has a critical impact on the bonding between applied materials and concrete, hence their efficacy in enhancing the durability of concrete.