The ratio of water to cementitious materials in a concrete mix is recognized as a prime determinant of the strength and ultimate durability of the concrete. In 1994, Troxler Electronic Laboratories introduced the Model 4430 Nuclear Water/Cement Ratio Gauge - a gauge designed to measure the water to cement ratio in fresh concrete sequentially. The HITEC volunteer panel directed this project to evaluate the gauge, and planned it to cover four phases: computer simulations, laboratory testing, precision and bias evaluation, and field demonstrations. This report outlines the HITEC evaluation and key findings for the Troxler gauge.