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In cold regions, calcium and magnesium chloride deicing salts damage concrete pavements due to the formation of certain deleterious chemical phases, including calcium oxychloride. While there is much research at a cement paste-scale, damage in concrete has been less studied. In this study, we evaluate concrete damage due to calcium and magnesium chloride and explain the roles of supplementary cementitious materials (SCM) replacement level, air entrainment, salt type, and exposure conditions in damage development. Various non-destructive test methods including bulk resistivity, mass change, and visual damage assessment were used to monitor the damage over time. Damage was reduced as the SCM replacement level and air content increased, regardless of exposure conditions. Bulk resistivity and visual assessment were promising indicators of damage. The product of 91-day bulk resistivity and the air content predicted concrete performance when exposed to concentrated deicing salts. Based on several criteria, mixtures with 20% fly ash replacement level or 35% slag mitigated damage significantly when the air content was greater than 5% by concrete volume. Damage mitigation mechanisms of SCM and air are discussed. [ABSTRACT FROM AUTHOR]

Abstract Although calcium oxychloride (Ca-Oxy) is known to damage cementitious materials exposed to calcium chloride (CaCl2) deicers, there is little direct observation of Ca-Oxy in the field due to its instability. This paper uses optical microscopy (OM) and scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX) to detect the formed Ca-Oxy and quantify its associated damage in a field mortar subject to freeze-thaw cycles and deicer application. The characterized damage in the field mortar is compared to that in lab-cast portland cement paste and mortar which are submerged in a CaCl2 solution of 25 wt.% under freeze-thaw cycles (− 8 to 25 °C). The field and lab-cast mortars show similar cracking patterns that are parallel to the exposure surface with a variation of 30–45° in the preferred orientation due to the constraints of sand particles. During each lab-controlled freeze-thaw cycle, the high CaCl2 concentration of 25 wt.% stabilizes the formed Ca-Oxy, which continually damages the mortar and eventually results in 3–4 times higher crack density compared to that in the field mortar. SEM-EDX analysis confirms the presence of secondary deposits including Friedel’s salt, ettringite and Ca-Oxy. Image analysis on thin section photomicrographs shows a reduction of 86.4% in calcium hydroxide (Ca(OH)2) content in the damaged field mortar compared to the undamaged field mortar, suggesting significant leaching of Ca(OH)2 to form Ca-Oxy due to the deicer application.

The formation of calcium oxychloride in cold conditions due to a reaction between calcium chloride deicing salt and calcium hydroxide in the concrete causes substantial damage to pavement concretes. In this study, the role of supplementary cementitious materials (SCMs) in mitigating damage in cement pastes and mortars exposed to highly concentrated CaCl2 solutions and low temperatures is elucidated. Cementitious paste and mortar mixtures designed with different SCM replacement levels were prepared and immersed in 25% CaCl2 solutions and subject to low-temperature cycles (− 8–25 °C) for 360 days (180 cycles). Damage was reduced as the SCM replacement level and curing time were increased, as confirmed by bulk resistivity, visual observation, and light microscopy measurements. Substantial differences between paste and mortar behavior were observed with the mortars outperforming pastes. [ABSTRACT FROM AUTHOR]

Calcium oxychloride formed in concrete exposed to a calcium chloride (CaCl 2) solution may reduce the durability of cementitious materials. A thermodynamic modeling technique is employed to predict the phase assemblage of the hardened cement paste (HCP) at various temperatures, CaCl 2 concentrations, and types and dosages of supplementary cementitious materials (SCMs) and to explore the degradation mechanism of HCP subjected to the CaCl 2 attack. The results indicate that monocarbonate decomposes under CaCl 2 attack to generate Kuzel's salt, and Kuzel's salt is then replaced by Friedel's salt at an even higher CaCl 2 concentration, while calcium hydroxide (CH) transforms into 3-1-12. The strength loss in HCP is directly proportional to the volume ratio of the solid phases in the HCP before and after chloride attack. Increasing the replacement level of silica fume (SF), fly ash (FA), slag (SL), or metakaolin (MK) reduces the amounts of CH and 3-1-12 formed in HCP. [Display omitted] • Reliable thermodynamic phase diagrams of the Ca(OH) 2 -CaCl 2 -H 2 O system at 5 °C and 25 °C are constructed. • The relationship between the amount of calcium oxychloride formed and CaCl 2 concentration and temperature is established. • 3Ca(OH) 2 ·CaCl 2 ·12H 2 O forms more readily as temperature lowers, whereas higher temperature promotes the formation of CaClOH. • The volume ratio of all solid phases in the HCP after and before chloride attack and strength loss are directly proportional. [ABSTRACT FROM AUTHOR]

Abstract In cementitious materials exposed to solutions containing chloride, chloride binding typically results from the chemical reactions between chloride ions and aluminate phases to form Friedel's salt, and the interaction between chloride ions and calcium silicate hydrates (C S H). Calcium oxychloride can also form when Ca(OH) 2 in cementitious materials reacts with CaCl 2 solutions. This paper examines the chloride binding of hydrated cement pastes containing fly ash exposed to CaCl 2 solutions of varying concentrations at 5 and 23 °C. Thermogravimetric analysis was used to quantify the chloride binding associated with Friedel's salt and calcium oxychloride. The amount of bound chloride by Friedel's salt is relatively independent of the exposure temperature, and as the chloride concentration [Cl−] increases, it increases until a plateau is reached at [Cl−] greater than 2 M. The addition of fly ash results in an increase in the chloride binding due to Friedel's salt. A lower exposure temperature leads to a greater amount of bound chloride associated with calcium oxychloride. In this study, no chloride binding associated with calcium oxychloride was observed in the cement pastes with 40% and 60% fly ash. The temperature-dependent chloride binding associated with C S H is a significant portion of the total chloride binding (19.8 %–70.8%) when cement pastes are exposed to CaCl 2 solutions. As the replacement level of fly ash increases, the chloride binding by C S H increases first and then decreases. The amount of bound chloride by C S H increases linearly as the pH of the exposure solution decreases. [ABSTRACT FROM AUTHOR]

This study reports the significant effect of CaCl 2 on strength improvement in CaO-activated Class F fly ash system. In these systems, the presence of CaCl 2 promotes (1) a higher degree of fly ash dissolution, (2) increasing C-S-H formation, and (3) an overall reduction of pore size and volume, resulting in increased strength. However, while more C-S-H, which is responsible for strength increase, was produced with higher CaCl 2 content, extreme doses of CaCl 2 resulted in strength degradation; more importantly, the best quantity of CaCl 2 for the greatest strength was dependent on the water-to-binder weight ratio (w/b). This dependency was closely related to the formation of calcium oxychloride, which generally causes severe expansive cracking and depends on w/b. [ABSTRACT FROM AUTHOR]

This study investigates the effects of continuous deicer exposure on the performance of pavement concretes. For this purpose, the differences in the compressive strength, the changes in the dynamic modulus of elasticity (DME) and the depth of chloride ingress were evaluated during and after the exposure period. Eight different concrete mixtures containing two types of coarse aggregates (i.e. air-cooled blast furnace slag (ACBFS) and natural dolomite) and four types of binder systems (i.e. plain Type I ordinary portland cement (OPC) and three combinations of OPC with fly ash (FA) and/or slag cement (SC)) were examined. These mixtures were exposed to three types of deicers (i.e. MgCl 2 , CaCl 2 , and NaCl) combined with two different exposure conditions (i.e. freezing-thawing (FT) and wetting-drying (WD)). In cold climates, these exposure conditions are the primary durability challenges that promote the physical deterioration of concrete pavements. The results indicated that among the studied deicers, CaCl 2 had the most destructive effect on the tested concretes while NaCl was found to promote the deepest level of chloride ingress yet was shown to have the least damaging impact on concretes. The microstructure evaluation revealed that the mechanism of concrete deterioration due to the deicer exposure involved chemical reactions between the deicers and concrete hydration products. The use of FA or SC as partial replacements for OPC can offset the detrimental effects of both deicers and FT/WD cycles. [ABSTRACT FROM AUTHOR]

Calcium chloride (CaCl 2 ) can react with calcium hydroxide (Ca(OH) 2 ) to form calcium oxychloride which can reduce flexural strength and damage concrete. This paper aims to characterize the reduction in flexural strength of cement pastes exposed to CaCl 2 solutions using the ball-on-three-balls test. The amounts of Ca(OH) 2 and calcium oxychloride in the cement paste are measured using thermogravimetric analysis and low-temperature differential scanning calorimetry, respectively. The volume change that occurs as a result of the reactions between the cement paste and CaCl 2 is also measured. The reduction in flexural strength increases as the concentration of the CaCl 2 solution increases and the exposure temperature decreases. The flexural strength reduction can be mitigated by increasing the amount of supplementary cementitious materials (fly ash) in the cement pastes. Lowering the water-cementitious materials ratio also reduces the flexural strength reduction. The flexural strength reduction is correlated with the amount of calcium oxychloride and the volume change in the cement pastes exposed to the CaCl 2 solution. While the flexural strength reduction is believed to be primarily due to the formation of calcium oxychloride, the formation of Friedel's salt and Kuzel's salt also contributes to the flexural strength reduction. [ABSTRACT FROM AUTHOR]

Formation of complex salts (oxychlorides) has been suspected for causing chemical degradation of concrete in cold regions. In this study, conditioned mode (controlled temperature and relative humidity) environmental scanning electron microscopy was specifically used to minimize changes in the crystal structures of oxychlorides phases and thus reliably capture their unaltered morphology and existence/effects on concrete exposed to different de-icing salts under two different environmental conditions (constant low temperature and wetting/drying (W/D) cycles). Formation of acicular flattened blades of 3- and 5-form magnesium oxychloride (MOX) and tiny fibrous crystals as well as subhedral pseudo-hexagonal calcium oxychloride plates (COX) were found in deteriorated concrete specimens, depending on the type of solution. The reversible formation of hydrous and anhydrous COX during W/D cycles had a significant effect on aggravating the kinetics of damage of concrete in this exposure. The combined salt (MgCl 2 + CaCl 2 ), which simulates using a synergistic maintenance and protective strategy for concrete pavements in winter, was the most aggressive solution; thus, this practice should be cautiously reconsidered. The incorporation of 30% fly ash had a pronounced effect on improving the concrete resistance to damage as reflected by sound mechanical properties and longevity. Also, the performance of concrete was much enhanced when an innovative supplementary cementitious material, nanosilica, was incorporated in the cementitious system. [ABSTRACT FROM AUTHOR]

This paper discusses the role of supplementary cementitious materials (SCM) in reducing damage caused by calcium oxychloride formation. Calcium oxychloride is a destructive product of a reaction between calcium hydroxide (CH) that exists in a cementitious matrix and CaCl 2 that can enter the pores of the matrix when it is used as a deicing salt. Paste samples were prepared where a percentage of ordinary portland cement was replaced with various types of SCM (including fly ash, slag, and silica fume). This paper examined the amount of calcium oxychloride that formed using low-temperature differential scanning calorimetry, and damage development detected using acoustic emission. Thermogravimetric analysis was also performed to determine the relationship between the amount of CH in cementitious materials and the amount of calcium oxychloride formation. The results show that the use of SCM is effective in reducing the calcium oxychloride formation and resulting damage when cementitious materials are exposed to various compositions of solution containing CaCl 2 . The explanation of the benefit of using SCM is that it can reduce the calcium oxychloride formation due to a reduction in the amount of CH in the cementitious materials through pozzolanic reaction and dilution of cement. As a result, cementitious materials with SCM exposed to CaCl 2 may experience less damage and have a longer service life. [ABSTRACT FROM AUTHOR]

Chloride-based deicing salt solutions can react with the calcium hydroxide in the cementitious matrix, leading to the formation of calcium oxychloride. Calcium oxychloride formation has been implicated in the premature deterioration of pavement joints and concrete flatwork across cold regions in North America. This study examines the formation of calcium oxychloride in the presence of blends of different chloride-based deicing salts (sodium and calcium chloride). This evaluation was performed using several plain cementitious pastes and pastes with fly ash, slag, and silica fume used as supplementary cementitious materials. Fly ash and slag were used at 20% replacement levels and the silica fume was used at 3 and 6% replacement levels. Thermogravimetric analysis was used to quantify the amount of calcium hydroxide, and low-temperature differential scanning calorimetry was used to quantify the amount of calcium oxychloride formed. When the salt blends consist of less than 20% of calcium chloride by mass, the amount of calcium oxychloride that forms is low and does not depend on the calcium hydroxide content in the pastes. When the salt blends consist of more than 20% of calcium chloride by mass, the amount of calcium oxychloride that forms depends on the calcium hydroxide content in the paste and increases with calcium hydroxide content. This suggests two strategies to mitigate the amount of calcium oxychloride that is formed: reduction in the amount of calcium hydroxide in the pastes through use of supplementary cementitious materials, and the use of deicing salt blends that include lower amounts of calcium chloride. A model is developed to estimate the amount of calcium oxychloride formed in mixtures, given the calcium hydroxide and calcium chloride contents. [ABSTRACT FROM AUTHOR]

Some jointed plain concrete pavements in the midwestern region of the United States of America have exhibited damage at the joints. This damage manifests itself in cracking and spalling in a small section (approximately 100 mm wide) along joints. These cracks may be due to either freeze-thaw cycling of concrete with a high degree of saturation or chemical reactions that occur between the deicing salt and the cementitious matrix. For example, deicing salts (e.g., CaCl 2 MgCl 2 ) may react with the cementitious matrix leading to the formation of calcium oxychloride. The formation of calcium oxychloride leads to matrix damage that results in the cracking and spalling of the concrete. The objective of this paper is to document the effect of carbonation on the potential for calcium oxychloride formation in a cementitious matrix. This paper examines ground hydrated cement paste powder made of different ordinary portland cements and portland cement containing fly ash, slag or silica fume. Each of these materials are tested for their potential to react with CaCl 2 after exposure to different levels of carbonation. The results indicate that the potential of calcium oxychloride formation decreases with the increase in the degree of carbonation. For long carbonation durations or higher degree of carbonations, there is no calcium oxychloride formation even if the calcium hydroxide is not totally carbonated. It appears that this is due to the fact that carbonation reaction creates a calcite barrier around the remaining calcium hydroxide. The calcite barrier reduces the potential for reaction between calcium hydroxide with the deicing salt. This work indicates that in addition to previous work that has shown that calcium oxychloride formation can be reduced with the use of supplementary cementitious materials and topical treatments (sealers), carbonation is a factor that should be considered in determining the amount of calcium oxychloride that can form in a cementitious matrix. [ABSTRACT FROM AUTHOR]

Calcium and magnesium deicing salts may damage concrete due to calcium oxychloride formation (CaOXY). Previous work has shown that replacing a portion of the cement in a mixture with supplementary cementitious materials reduce CaOXY formation. AASHTO PP-84 was developed to help specify damage-resistant mixtures by limiting the CaOXY amount in paste. This limit was established based on empirical observations; however, this did not consider other aspects of the mixture such as paste volume or air content. This paper investigates how fluid absorption, paste volume, and air content are all key parameters in determining damage from CaOXY. Concrete with a higher paste volume has more CaOXY and is more susceptible to damage. Concrete with a higher air content is less susceptible to damage as the voids provide space for fluid absorption and CaOXY formation; however this only occurs for mixtures with a specific range of calcium hydroxide (Ca(OH) 2) (between 7 and 12 g Ca(OH) 2 /100 g paste). This paper incorporates these factors to provide a more comprehensive explanation for CaOXY-induced damage in concrete. • Calcium and magnesium deicing salts may damage concrete due to calcium oxychloride formation (CaOXY). • Concrete with a higher paste volume has more CaOXY and is more susceptible to damage. • Concrete with a higher air content is less susceptible to CaOXY-damage for mixtures with Ca(OH) 2 content between 7-12 g /100 g paste. • The absorption of fluid appears necessary for substantial CaOXY-induced damage. [ABSTRACT FROM AUTHOR]

The conventional CaCl 2 –H 2 O phase diagram is often used to describe how calcium chloride behaves when it is used on a concrete pavement undergoing freeze-thaw damage. However, the chemistry of the concrete can alter the appropriateness of using the CaCl 2 –H 2 O phase diagram. This study shows that the Ca(OH) 2 present in a hydrated portland cement can interact with CaCl 2 solution creating a behavior that is similar to that observed in isoplethal sections of a ternary phase diagram for a Ca(OH) 2 –CaCl 2 –H 2 O system. As such, it is suggested that such isoplethal sections provide a reasonable model that can be used to describe the behavior of concrete exposed to CaCl 2 solution as the temperature changes. Specifically, the Ca(OH) 2 can react with CaCl 2 and H 2 O resulting in the formation of calcium oxychloride. The formation of the calcium oxychloride is expansive and can produce damage in concrete at temperatures above freezing. Its formation can also cause a significant decrease in fluid ingress into concrete. For solutions with CaCl 2 concentrations greater than about 11.3% (by mass), it is found that calcium oxychloride forms rapidly and is stable at room temperature (23 °C). [ABSTRACT FROM AUTHOR]

Magnesium chloride (MgCl 2 ) is used in deicing applications due to its capability to depress freezing temperatures to a lower point than other salts such as sodium chloride (NaCl). The constituents of concrete (i.e., pores solution, calcium hydroxide, aluminate phases, and calcium silicate hydrate gel) can alter the MgCl 2 –H 2 O phase diagram when it is used to interpret the performance of concrete. Different chemical reactions may concurrently occur between MgCl 2 and cementitious constituents to form brucite, Friedel’s salts, magnesium silicate hydrate, magnesium oxychloride, and/or secondary calcium oxychloride. In this study, it was observed that MgCl 2 can be entirely consumed in concrete by the chemical reactions and produce CaCl 2 . As such, it was found that MgCl 2 interacts significantly with a cementitious material and it follows a response that is more similar to the Ca(OH) 2 –CaCl 2 –H 2 O phase diagram than that of the MgCl 2 –H 2 O phase diagram. Mortar samples exposed to low concentration MgCl 2 solutions (<10% by mass) for a short duration of freezing and thawing showed damage due to ice formation, while for higher concentrations (⩾10% by mass), the damage was most likely due to the chemical reactions between MgCl 2 and cementitious constituents at room temperature (23 °C). These chemical reactions occurred rapidly (within 5–10 min) and caused a significant decrease in subsequent fluid ingress into exposed concrete. [ABSTRACT FROM AUTHOR]

• Fly ash and entrained air are used to mitigate calcium oxychloride deterioration in concrete. • 15% fly ash with 5% entrained air mitigated most calcium oxychloride deterioration in flexural strength concrete specimens stored in a 30% CaCl 2 solution. • 30% fly ash with 5% entrained air mitigated most calcium oxychloride in compressive strength concrete specimens stored in a 30% CaCl 2 solution. • Class C fly ash generally mitigated strength loss to a greater extent than Class F fly ash. Calcium oxychloride is a serious deterioration mechanism affecting concrete pavements. In order to mitigate calcium oxychloride deterioration in concrete, fly ash is used as partial cement replacement in conjunction with entrained air. Concrete specimens were stored in a 30% calcium chloride solution at 5 °C for 202 days. Following storage, specimens were evaluated through compressive and flexural strength loss along with mass change, length change, and chloride penetration. Results indicate that a partial cement replacement with 15% fly ash mitigates deterioration in concrete specimens when tested for flexural strength loss; however, 30% or more fly ash is needed for similar mitigation based on compressive strength. Further, results indicate that specimens cast with 5% entrained air outperform those without air entrainment. Class C fly ash generally mitigated strength loss to a greater extent than Class F fly ash. [ABSTRACT FROM AUTHOR]

The stable quaternary diagram for the system CaO-Al2O3-CaCl2-H2O at 23±4 °C has been constructed. Among the phases in this system are the calcium oxychlorides Ca(OH)2.CaCl2.H2O and 3Ca(OH)2.CaCl2.12H2O. The formation of Friedel''s salt (FS) and calcium oxychlorides provides a mechanism for chloride binding in Portland cement concrete. The compatibility relationships involving these compounds, FS and Ca(OH)2, were established empirically, and 3Ca(OH)2.CaCl2.12H2O was found not to coexist in equilibrium with FS. The solubility behaviors of these compounds may play a role in affecting temperature-dependent corrosion rates. Additionally, the formation of oxychlorides from solutions containing elevated concentrations of NaCl may provide a mechanism by which ASR is facilitated. [Copyright &y& Elsevier]

Pavement damage occurs in cold-region concrete exposed to high concentrations of calcium chloride (CaCl 2). The damage is caused by a combination of conventional freeze-thaw damage and the formation of a deleterious phase known as calcium oxychloride from a reaction between CaCl 2 and calcium hydroxide in the concrete. Much research has focused on calcium oxychloride mitigation in cement pastes, but not on concrete damage due to calcium oxychloride. In this study, the synergistic roles of air and supplementary cementitious materials (SCMs) in reducing damage in concrete exposed to high concentrations of CaCl 2 and freeze-thaw conditions is studied. Concrete mixtures were made with different SCM replacement levels and air contents and immersed in 25% CaCl 2 solutions and subject to freeze-thaw cycles (−8 °C–25 °C) for 600 days. Bulk resistivity and visual assessment of damage were excellent descriptors of the damage progression. Damage was reduced as the SCM content and air content were increased. Mixtures which had 20% SCM and 8% air and mixtures which had 35% SCM and more than 4% air showed strong durability against calcium oxychloride damage. [ABSTRACT FROM AUTHOR]

Chloride-based deicers, especially CaCl 2 and MgCl 2 , can damage cementitious materials due to the formation of mineral phases such as calcium oxychloride and brucite. However, there are only limited direct observations of calcium oxychloride formed in cementitious materials in the field. This paper uses petrographic methods to evaluate damage of an in-service cementitious mortar substrate subject to freeze-thaw cycles and deicers for six years. The amount of calcium hydroxide in the mortar was quantified using thermogravimetric analysis. Changes in hydration products and microstructure were characterized by optical microscopy. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy was used to examine the morphology and elemental composition of secondary deposits related to the deicer damage. The mortar with less than 3% air exhibits horizontal cracks and microcracks cutting around aggregate particles. The cracks and microcracks are partially filled with calcium oxychloride due to the application of CaCl 2. A densified crust of brucite and calcite, likely associated with the usage of MgCl 2 , covers the top surface of the damaged mortar. The deicer exposure results in leaching of calcium hydroxide mainly due to the formation of calcium oxychloride. Calcium leaching increases the apparent paste porosity in the damaged mortar, which likely weakens the physicomechanical properties of the mortar and accelerates the ingress of external deicer solutions. Moreover, the deicer application results in air-void-filling by calcium oxychloride and secondary ettringite, which may reduce the space available to release the internal stresses associated with ice formation and thus compromises the freeze-thaw durability. [ABSTRACT FROM AUTHOR]

• Fly ash is used to mitigate calcium oxychloride damage in cementitious paste. • Calcium oxychloride protection threshold of 15 g/100 g paste is evaluated. • Compressive strength results generally validate the current threshold. • Mass change results indicate the current threshold is conservative. Calcium oxychloride (CAOXY) formation is a deterioration mechanism known to cause joint damage in concrete pavements. The accepted CAOXY mitigation threshold in paste is 15 g/100 g paste; however, this limit was developed using flexural strength testing of pastes. This investigation seeks to verify this threshold using compressive strength and mass change testing. Cementitious pastes were cast with portland cement and fly ash (up to 50% mass). Specimens were stored in a 30% mass CaCl 2 at 5 °C to accelerate deterioration. Visual observations, thermogravimetric analysis, low-temperature differential scanning calorimetry, mass change, and compressive strength results were recorded. Partial replacement of cement with fly ash reduces the Ca(OH) 2 , CAOXY, and damage levels. Using mass change, a threshold at which no damage occurs is established at 20 g/100 g paste, indicating that the current threshold is conservative. For compressive strength, while increasing the amount of fly ash reduces damage, damage is noted in all specimens tested; however, strength loss noted in this work is similar to the research which established the current threshold. Therefore, the compressive strength results generally validate the CAOXY threshold level of 15 g/100 g paste. Careful correlations between paste and concrete damage are needed in order to further verify the threshold value. [ABSTRACT FROM AUTHOR]

Deicing salts have long been known to cause deterioration in concrete pavements. Freeze/thaw, surface scaling, and reinforcement corrosion are well documented deterioration mechanisms. However, another mechanism exists causing severe concrete damage that is much less understood. This deterioration is due to the formation of calcium oxychloride, from chemical interactions between the cementitious paste and certain chloride-based deicing salts. The basic chemical structure of calcium oxychloride, with slight variations, has been reported in deteriorated samples. Ideas have been postulated about failure mechanisms associated with the formation of calcium oxychloride. Further, testing techniques such as thermogravimetric analysis, low-temperature differential scanning calorimetry, and volume change measurements have been successfully utilized to better understand/quantify calcium oxychloride. Mitigation techniques to minimize the impact of calcium oxychloride include reducing cement content through the use of supplementary cementitious materials or other means, the use of adequate air entrainment, preferential carbonation, and the use of concrete sealants. This review of the literature highlights the current understanding of calcium oxychloride, provides best practice guidance and identifies new areas of research needed in order to effectively mitigate calcium oxychloride damage in concrete pavements. [ABSTRACT FROM AUTHOR]