This research was inspired by the need to optimize the mix design of electrically conductive concrete (ECON) for field implementation. Carbon fiber was used for producing ECON with different mixing proportions and constituents. Calcium nitrite-based corrosion inhibitor admixture and methylcellulose were used as conductivity-enhancing agent (CEA) and fiber-dispersive agent (FDA) respectively. Five easy-to-change mix design variables were evaluated for their effects on electrical conductivity and strength of ECON: carbon fiber dosage, fiber length, coarse-to-fine aggregate volume ratio (C/F), CEA dosage, and FDA dosage. The results approved the effectiveness of the applied CEA in improving electrical conductivity while positively influencing strength. Conductivity was significantly influenced by: fiber content, C/F, fiber length, and CEA dosage. The dosages of Fiber, CEA, and FDA exerted significant influence on compressive strength. C/F and FDA dosage were significant variables influencing flexural strength.

Traditional methods of removing snow/ice from pavements involve application of deicing salts and mechanical removal that carry environmental concerns. In this study, the feasibility of applying carbon fiberbased electrically conductive concrete (ECON) in heated pavement systems (HPS) as an alternative to traditional methods was investigated. Optimum carbon fiber dosage to achieve desirable electrical conductivity and avoid excessive fiber use was determined by studying carbon fiber percolation in different cementitious composites. System design was evaluated by finite element (FE) analysis. Heating performance in terms of energy consumption regime was studied by quasi-long-term (460-day) experimental study using a prototype ECON slab. Percolation transition zone of carbon fiber in paste, mortar, and concrete were respectively 0.25-1% (Vol.), 0.6-1% (Vol.), and 0.5-0.75% (Vol.). Optimum fiber dosage in ECON with respect to conductivity was 0.75%, resulting in volume conductivity of 1.86 × 10−2 (S/cm) at 28 days and 1.22 × 10−2(S/cm) at 460 days of age. Electrical-energy-to-heat-energy conversion efficiency decreased from 66% at 28 days to 50% at 460-day age. The results showed that the studied technology could be effectively applied for ice/snow melting on pavement surfaces and provide a feasible alternative to traditional methods if the ECON mixing proportions and system configurations are made with necessary precautions.

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Millions of dollars are annually spent for ice or snow removal from the roadways and airport paved surfaces in cold regions. The presence of snow or ice on paved areas can cause traffic accidents and financial loss because of flight cancellations or delays. For mitigating winter pavement maintenance issues, the use of superhydrophobic (super-water-repellent) coating techniques is gaining attention as a smart and cost-effective alternative to traditional snow and ice removal practices. This study focuses on creating, characterizing, and evaluating innovative superhydrophobic coatings on asphalt concrete surfaces for ice- and snow-free flexible pavement applications. The layer-by-layer (LBL) method was used to create an asphalt concrete surface coating with polytetrafluoroethylene (PTFE) as a well-known super-ice- and super-water-repellent material. Superhydrophobicity and skid resistance of the coated asphalt concrete surface were characterized by the water contact angle, the work of adhesion, and the coefficient of friction at the microtexture level. These properties were evaluated for test variables including spray times and dosage rates of PTFE under a statistical design–based experimental test program. The measurement results indicate that uses of the LBL method for spray-depositing the PTFE particles and the microtribometer for measuring coefficient of friction at the microtexture level are promising methods for creating and characterizing superhydrophobic coatings on asphalt concrete. The results of statistical analyses indicate that the spray time and dosage of PTFE significantly affect the ability of a coated flexible pavement to be icephobic or superhydrophobic and skid resistant.

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