Bio-Based Renewable Additives for Anti-Icing Applications (Phase II)

The performance and impacts of several agro-based anti-icers along with a traditional chloride-based anti-icer (salt brine) were evaluated. A statistical design of experiments (central composite design) was employed for developing anti-icing liquids consisting of cost-competitive chemicals such as agro-based compounds (e.g., Concord grape extract and glycerin), sodium chloride, sodium metasilicate, and sodium formate. The following experimentally obtained parameters were examined as a function of the formulation design: ice-melting capacity at 25°F (−3.9°C), splitting strength of Portland cement mortar samples after 10 freeze-thaw/deicer cycles, corrosion rate of C1010 carbon steel after 24-hour immersion, and impact on asphalt binder stiffness and m-value. One viable formula (“best performer”) was tested for thermal properties by measuring its differential scanning calorimetry (DSC) thermograms, the friction coefficient of asphalt pavement treated by this anti-icing formulation (vs. 23 wt.% NaCl and beet juice blend) at 25°F after being applied at 30 gallons per lane mile (1 hour after simulated trafficking and plowing), and other properties (pH, oxygen demand in COD). Laboratory data shed light on the selection and formulation of innovative agro-based snow- and ice-control chemicals that can significantly reduce the costs of winter maintenance operations

The Deleterious Chemical Effects of Concentrated Deicing Solutions on Portland Cement Concrete, Literature Review, TR-480, 2008

This research project investigated the effects of concentrated brines of magnesium chloride, calcium chloride, sodium chloride, and calcium magnesium acetate on portland cement concrete. Although known to be effective at deicing and anti-icing, the deleterious effects these chemicals may have on concrete have not been well documented. As a result of this research, it was determined that there is significant evidence that magnesium chloride and calcium chloride chemically interact with hardened portland cement paste in concrete resulting in expansive cracking, increased permeability, and a significant loss in compressive strength. Although the same effects were not seen with sodium chloride brines, it was shown that sodium chloride brines have the highest rate of ingress into hardened concrete. This latter fact is significant with respect to corrosion of embedded steel. The mechanism for attack of hardened cement paste varies with deicer chemical but in general, a chemical reaction between chlorides and cement hydration products results in the dissolution of the hardened cement paste and formation of oxychloride phases, which are expansive. The chemical attack of the hardened cement paste is significantly reduced if supplementary cementitious materials are included in the concrete mixture. Both coal fly ash and ground granulated blast furnace slag were found to be effective at mitigating the chemical attack caused by the deicers tested. In the tests performed, ground granulated blast furnace slag performed better as a mitigation strategy as compared to coal fly ash. Additionally, siloxane and silane sealants were effective at slowing the ingress of deicing chemicals into the concrete and thereby reducing the observed distress. In general, the siloxane sealant appeared to be more effective than the silane, but both were effective and should be considered as a maintenance strategy

Bio-based Renewable Additives for Anti-icing Applications (Phase I)

The performance and impacts of several bio-based anti-icers along with a traditional chloride-based anti-icer (salt brine) were evaluated. A statistical design of experiments (uniform design) was employed for developing anti-icing liquids consisting of cost-competitive chemicals such as bio-based compounds (e.g., sugar beet extract and dandelion extract), rock salt, sodium metasilicate, and sodium formate. The following experimentally obtained parameters were examined as a function of the formulation design: ice-melting capacity and ice penetration at 25°F (−3.9°C) and 15°F (−9.4°C), compressive strength of Portland cement mortar samples after 10 freezethaw/deicer cycles, corrosion rate of C1010 carbon steel after 24-hour immersion, and impact on asphalt binder’s stiffness. One viable formula (“best performer”) was tested for freezing point depression phase diagram (ASTM D1177-88) and the friction coefficient of asphalt pavement treated by this anti-icing formulation (vs. 23 wt.% NaCl) at a certain temperature near 25°F or 30°F after being applied at 30 gallons per lane mile (1 hour after simulated trafficking and plowing). Laboratory data shed light on the selection and formulation of innovative bio-based snow and ice control chemicals that can significantly reduce the costs of winter maintenance operations. This exploratory investigation contributes to more systematic study of optimizing “greener” anti-icers using renewable resources

Guide to the Prevention and Restoration of Early Joint Deterioration in Concrete Pavements TR-697, July 2017

In recent years, premature joint deterioration has occurred in concrete pavements in snowbelt states. Research has found two primary mechanisms behind the deterioration: (1) Certain deicing/anti-icing salts—calcium chloride and magnesium chloride— react with cement paste to form calcium oxychloride, an expansive material that is detrimental to concrete pavement performance (sodium chloride is not as reactive). (2) Freeze-thaw damage occurs in joints when a critical degree of saturation is reached or exceeded; salts can exacerbate the problem by keeping joints in a high state of saturation. As a result of these findings, the Iowa Highway Research Board commissioned the National Concrete Pavement Technology Center to write this guide. The primary goal is to help Iowa’s concrete pavement engineers understand the causes of premature joint deterioration, focusing on deterioration due to salt reactivity and joint saturation. The guide also discusses strategies for preventing or limiting such deterioration. One strategy is to limit applications of calcium chloride and magnesium chloride in order to mitigate the formation of calcium oxychloride. Another critical strategy is to keep the saturation level of the concrete below approximately 85 percent. This can be accomplished by designing a durable concrete that includes an adequate air-void system, supplementary cementitious materials, and a low water-to-cementitious-materials ratio, as well as by providing good drainage to the pavement system and following other best practices in concrete pavement design, construction, and maintenance. This guide also provides a summary of joint repair and restoration strategies, including a decision flow chart. Finally, the guide offers guidelines for developing project specifications, with appropriate references to Iowa DOT Standard Road Plans, Standard Specifications, and Instructional Memoranda

Towards an adequate deicing salt scaling resistance of high-volume fly ash (HVFA) concrete and concrete with superabsorbent polymers (SAPs)

The deicing salt scaling resistance has been investigated for two types of concrete, i.e., air entrained high-volume fly ash (HVFA) concrete with a 50% cement replacement and non-air entrained concrete containing superabsorbent polymers (SAPs). A full characterization of their air void systems from the moment of casting until the freeze/thaw test was also done. Due to the presence of the highly AEA adsorptive fly ash an increased AEA dosage (7.0 ml/kg binder) was needed to achieve an adequate air void system in terms of air content and spacing factor to keep salt scaling within acceptable limits. For the novel non-air entrained concrete type with SAPs, which are able to absorb up to 500 times their weight in fluids, the salt scaling resistance is surprisingly high. The microstructural analysis revealed the formation of macro-pores due to these SAPs, creating an air void system as can be found in air-entrained concrete. Another advantage is that the strength of concrete with SAPs is much higher than for a conventional air-entrained concrete. This substantiates the further use of these SAPs as admixture in precast concrete road elements

Impact of Embedded Carbon Fiber Heating Panel on the Structural/Mechanical Performance of Roadway Pavement

INE/AUTC 12.3

The Deleterious Chemical Effects of Concentrated Deicing Solutions on Portland Cement Concrete, TR-480, Implementation Guide, 2008

This research project investigated the effects of concentrated brines of magnesium chloride, calcium chloride, sodium chloride, and calcium magnesium acetate on portland cement concrete. Although known to be effective at deicing and anti-icing, the deleterious effects these chemicals may have on concrete have not been well documented. As a result of this research, it was determined that there is significant evidence that magnesium chloride and calcium chloride chemically interact with hardened portland cement paste in concrete resulting in expansive cracking, increased permeability, and a significant loss in compressive strength. Although the same effects were not seen with sodium chloride brines, it was shown that sodium chloride brines have the highest rate of ingress into hardened concrete. This latter fact is significant with respect to corrosion of embedded steel. The mechanism for attack of hardened cement paste varies with deicer chemical but in general, a chemical reaction between chlorides and cement hydration products results in the dissolution of the hardened cement paste and formation of oxychloride phases, which are expansive. The chemical attack of the hardened cement paste is significantly reduced if supplementary cementitious materials are included in the concrete mixture. Both coal fly ash and ground granulated blast furnace slag were found to be effective at mitigating the chemical attack caused by the deicers tested. In the tests performed, ground granulated blast furnace slag performed better as a mitigation strategy as compared to coal fly ash. Additionally, siloxane and silane sealants were effective at slowing the ingress of deicing chemicals into the concrete and thereby reducing the observed distress. In general, the siloxane sealant appeared to be more effective than the silane, but both were effective and should be considered as a maintenance strategy

Experimental Study on an Electrical Deicing Technology Utilizing Carbon Fiber Tape

INE/AUTC 12.2

Development of durable “green” concrete exposed to deicing chemicals via synergistic use of locally available recycled materials and multi-scale modifiers

From the economic and social perspectives, the use of waste materials would not be attractive until their costs and quality can satisfy the construction requirements. In this study, a pure fly ash paste (PFAP) was developed in place of ordinary Portland cement paste (OPCP). This PFAP was prepared at room temperature and without direct alkali activation. The samples were prepared using only the as-received class C coal fly ash, water, and a very small amount of borax (Na2B4O7). On average, the PFAP featured 28-d compressive strength of about 36 MPa, and micro-nano hardness and elastic modulus 29% and 5%, higher than the OPCP, respectively. These mechanical and other properties of the PFAP make it a viable “green” construction binder suitable for a host of structural and non-structural applications. Advanced characterization of the raw material and PFAP pastes was employed to elucidate the hydration mechanisms of this “green” binder. The obtained knowledge sheds light on the role of class C CFA in the hydration process and may benefit the expanded use of various CFAs in cementitious materials