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

      Nazari, Mehdi Honarvar; Havens, Eden Adele; Shi, Xianming; Muthumani, Anburaj (Center for Environmentally Sustainable Transportation in Cold Climates, 2016-09-04)
      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.
    • Bio-Based Renewable Additives for Anti-Icing Applications (Phase II)

      Nazari, Mehdi Honarvar; Oh, Taekil; Ewing, Alexander Charlemagne; Okon, Deborah Ave; Avalos, Brandon; Alnuaimi, Eisa; Havens, Eden Adele; Shi, Xianming (Center for Environmentally Sustainable Transportation in Cold Climates, 2019-01-24)
      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.
    • Cost-Effective Use of Sustainable Cementitious Materials as Reactive Filter Media (Phase I)

      Li, Wenbing; Shi, Xianming (2019-08-31)
      This report presents a laboratory study on the use of nano SiO2 as modifier in crushed fines recycled concrete (CFRCs), coupled with thermal treatment, with the goal of fabricating a sustainable reactive medium to capture the chloride anions in deicer-laden stormwater runoff. A uniform design (UD) scheme was employed for the statistical design of experiments. Predictive models were developed based on the experimental data to quantify the influence of each design parameter on the effectiveness of removing Cl- ions from simulated stormwater. The models were verified, and then employed for predictions. Finally, the samples of different CFRCs modified by nano SiO2 and heating regimes were prepared under the optimal parameters identified via the Response Surface Methodology (RSM). The optimal processing of CRFCs include the use of admixing nano SiO2 at 0.3% (by mass), then heating the material at 525oC for 3h. The structure and properties of these CFRCs materials were characterized by XRD, FTIR, BET, SEM and EDS. These advanced characterization tools revealed that the modified CFRCs achieved great potential to chemically bind chloride anions. This work is expected to produce substantial benefits for highway agencies and other stakeholders of deicer stormwater runoff, through enhanced understanding of the efficacy and appropriateness of cementitious filter media in passive reactive systems for decreasing contaminant loading in stormwater runoff. The use of CRFCs as a low-cost sorbent will be economically attractive and environmentally sustainable, diverting them from waste stream and landfill and towards sustainable stormwater management.
    • Environmentally Friendly Pervious Concrete for Treating Deicer-Laden Stormwater: Phase I

      Xu, Gang; Shi, Xianming (Center for Environmentally Sustainable Transportation in Cold Climates, 2015-12-30)
      A graphene oxide-modified pervious concrete was developed by using low-reactivity, high-calcium fly ash as sole binder and chemical activators and other admixtures. The density, void ratio, mechanical strength, infiltration rate, Young’s modulus, freeze-deicer salt scaling, and degradation resistance of this pervious concrete were measured against three control groups. The test results indicate that graphene oxide modified fly ash pervious concrete is comparable to Portland cement pervious concrete. While the addition of 0.03% graphene oxide (by weight of fly ash) noticeably increased the compressive strength, split tensile strength, Young’s modulus, freeze-deicer salt scaling, and degradation resistance of fly ash pervious concrete, it reduced the void ratio and infiltration rate. The fly ash pervious concrete also showed unfavorable high initial loss during the freeze-deicer salt scaling test, which may be attributed to the low hydration degree of fly ash at early age. It is recommended that durability tests for fly ash concrete be performed at a later age.
    • Environmentally Friendly Pervious Concrete for Treating Deicer-Laden Stormwater: Phase II

      Xu, Gang; Shi, Xianming (2018-12)
      In Phase I of this project, graphene oxide (GO)-modified pervious concrete was developed using coal fly ash as the sole binder. The primary objectives of Phase II of this project were (1) to evaluate the stormwater infiltration capacity of GO-modified fly ash pervious concrete; (2) to evaluate the durability performance of GO-modified fly ash pervious concrete using freeze/thaw and salt resistance testing methods; and (3) to use advanced analytical tools to fully characterize the GO-modified fly ash binder. Test results indicate different degrees of reduction in concentrations of possible pollutants in stormwater—copper, zinc, sulphate, chloride, ammonia, nitrate, and total phosphate. The incorporation of GO significantly improved the resistance of pervious concrete to freeze/thaw cycles and ambient-temperature salt attack. The specimens were examined using X-ray diffraction, which revealed that the mineralogy and the chemical composition of fly ash pastes differ considerably from those of cement pastes. Nuclear magnetic resonance was used to study the chemical structure and ordering of different hydrates, and provided enhanced understanding of the freeze/thaw and salt scaling resistance of fly ash pervious concrete and the role of GO.
    • A Framework for Life Cycle Sustainability Assessment of Road Salt Used in Winter Maintenance Operations

      Cui, Na; Xie, Ning; Shi, Xianming (Center for Environmentally Sustainable Transportation in Cold Climates, 2016-12)
      It is important to assess from a holistic perspective the sustainability of road salt widely used in winter road maintenance (WRM) operations. The importance becomes increasingly apparent in light of competing priorities faced by roadway agencies, the need for collaborative decision-making, and growing concerns over the risks that road salt poses for motor vehicles, transportation infrastructure, and the natural environment. This project introduces the concept of Life Cycle Sustainability Assessment (LCSA), which combines Life Cycle Costing, Environmental Life Cycle Assessment, and Social Life Cycle Assessment. The combination captures the features of three pillars in sustainability: economic development, environmental preservation, and social progress. With this framework, it is possible to enable more informed and balanced decisions by considering the entire life cycle of road salt and accounting for the indirect impacts of applying road salt for snow and ice control. This project proposes a LCSA framework of road salt, which examines the three branches of LCSA, their relationships in the integrated framework, and the complexities and caveats in the LCSA. While this framework is a first step in the right direction, we envision that it will be improved and enriched by continued research and may serve as a template for the LCSA of other WRM products, technologies, and practices.
    • A New Sustainable Additive for Anti-Icing Pavement

      Zhang, Yan; Shi, Xianming (2019-08-30)
      Based on a review and synthesis of the state-of-the-art literature on asphalt pavement with anti-icing additives, this laboratory study developed an anti-icing asphalt pavement that incorporates innovative salt-storage additives with a sustained salt-release rate. These additives were prepared through a surface treatment approach, in which zeolite containing CaCl2 was coated by a porous epoxy layer. The anti-icing performances and mechanical properties of asphalt mixture with the obtained additives were investigated. The experimental results indicated that the anti-icing capability of asphalt mixture at both -3.9 °C (25°F) and -9.4 °C (15°F) was significantly improved by the addition of the additives, and the friction coefficient of the pavement at 60 min after moisture spray was 0.75 at -3.9 °C to 0.55 at -9.4 °C. Reducing the size of additives resulted in a further improved anti-icing capability. Under simulated conditions, the estimated effective anti-icing period of asphalt pavement with additives #8, #16, and #30 were 5.8 years, 9.9 years and 15.3 years, respectively. The incorporation of the additives exhibited negligible effect on the moisture damage resistance of asphalt mixture, and almost all the mixtures passed the WSDOT specification as well as the Wisconsin and Iowa specifications. The rutting resistance, mid-temperature (fatigue) cracking resistance, and low-temperature (thermal) cracking resistance of asphalt mixture improved due to the addition of these anti-icing additives to various extents.
    • Recent Advances in Sustainable Winter Road Operations – A Book Proposal

      Shi, Xianming (Center for Environmentally Sustainable Transportation in Cold Climates, 2017-08)
      Investing in winter transportation operations is essential and beneficial to the public and the economy. The U.S. economy cannot afford the cost of shutting down highways, airports, etc., during winter weather. In the northern U.S. and other cold-climate areas, winter maintenance operations are essential to ensure the safety, mobility, and productivity of transportation systems. Agencies are continually challenged to provide a high level of service and improve safety and mobility in a fiscally and environmentally responsible manner. To this end, it is desirable to use the most recent advances in the application of materials, practices, equipment, and other technologies. Such best practices are expected to improve the effectiveness and efficiency of winter operations, to optimize material usage, and to reduce associated annual spending, corrosion, and environmental impacts. Currently, no professional societies, scientific journals, or textbooks are dedicated solely to sustainable winter road operations, and key information is scattered across a variety of disciplines. The objective of the proposed book is to summarize the best practices and recent advances in sustainable winter road operations for the purposes of education and workforce development. This book is now in press and can be cited as follows: Shi, X., Fu, L. (2017). Sustainable Winter Road Operations (Eds.). ISBN: 978-1-119-18506-2. Wiley-Blackwell.
    • A Targeted Approach to High-Volume Fly Ash Concrete Pavement (Phase I)

      Du, Sen; Shi, Xianming (2018-12)
      Unlike the conventional method of admixing nanomaterials directly in fresh concrete mixture, a more targeted approach was explored. Specifically, nanomaterials were used to improve the interface between coarse aggregate and cement paste, by coating the coarse aggregate with cement paste that contained graphene oxide or nanosilica. Using coated coarse aggregates, the mechanical and transport properties of high-volume fly ash (HVFA) concrete were tested to evaluate the effect of nanomaterial coating on the interface transition zone of concrete. The compressive and splitting strengths of HVFA concrete at 3, 7, 14, and 28 days and the water sorptivity and chloride migration coefficient at 28 days were studied. Results show that nanomaterial-coated coarse aggregate can improve the transport properties of HVFA concrete by reducing permeability. However, no improvement was seen in the compressive and splitting strengths when incorporating coated coarse aggregate, compared with direct mixing of nanomaterials in fresh concrete. Resistance to freezing/thawing cycles and scanning electron microscope/energy dispersive X-ray spectroscopy of concrete samples were also investigated to obtain a more comprehensive and mechanistic understanding of nanomaterial coating.