The conductivity of porous normalNi/ZrO2‐Y2O3 cermets at 1000°C was determined as a function of Ni content between 15 and 50 volume percent (v/o) of total solids for two different zirconia particle sizes (23 and 47 m2/g). Below Ni contents of 30 v/o, ionic conduction through the zirconia phase dominated. At 30 v/o Ni, a greater than three order of magnitude increase in the conductivity was observed, corresponding to a change in mechanism to electronic conduction through the Ni phase. The conductivity of cermets made with a Ni content greater than 30 v/o Ni was found to decrease with increasing temperature between 700° and 1000°C. While the conductivity of the cermets with the larger particle size zirconia was higher by more than a factor of four, all the samples studied had the same activation energy, 5.7±0.1 normalkJ/normalmol . The increase in conductivity with zirconia particle size is attributed to improved Ni particle‐to‐particle contact, resulting from the Ni phase being able to cover more completely the surface of the zirconia matrix where it resides.

at 1000 °C has been measured as a function of the Ni content (15‐50 vol.%) using cermets with two different ZrO2 particle sizes.

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Polyphosphoric acid (PPA) has been used in 3.5% to 14% of the asphalt placed in the United States over the past 5 years. This represents up to 400 million tons of hot mix. As with all other components of the mix, testing is required to demonstrate the performance of PPA with each formulation of asphalt and aggregate, together with polymer, antistrip agents, and other additives that may be used. Results of the following tests are presented: dynamic shear rheometer, Hamburg, Lottman, and multiple stress creep and recovery tests on a matrix of a common asphalt with aggregate, three antistrip agents, two types of polymers, and PPA. Laboratory data for the materials tested show that the performance of PPA-modified asphalt can be improved with the addition of antistrip agents such as a phosphate ester, a particular polyamine compound, and hydrated lime. These findings hold true for cases where modification includes the use of polymers: styrene–butadiene–styrene and Elvaloy.