A construction control field test method for determining the cement content of freshly mixed soil-cement or roller-compacted concrete (RCC) is discussed. Typical Bureau of Reclamation practice is to establish the most economical mix design requiring the lowest possible cement content that meets both strength and durability specification criteria. Gradation characteristics of available borrow material can dictate mix designs having a significant percentage of plus 4.75-mm (No. 4) sieve-size particles. The ability to determine quickly and accurately the cement content of soil-cement or RCC as it is being placed is critical to help ensure that specification strength and durability requirements are being met. The heat of neutralization test method presented (as modified by the Bureau of Reclamation) has been found to be accurate to within ± 1 % of actual cement content for mix designs having cement contents of 3 to 16 % and up to 50 % plus 4.75-mm (No. 4) sieve-size particles; does not require the separation of plus 4.75-mm (No. 4) sieve-size material; and cement content determinations can be made using durable field equipment within 15 to 20 min. Precision and bias statements have been established for the test method in accordance with the ASTM Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction Materials (C 802) and the ASTM Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials (C 670) and are presented.