Abstract: A process for inhibiting acidic corrosion in the crown of a concrete sewer pipeline of the type created by the generation of sulfuric acid within the pipeline and a lowering of the pH at the surface of the concrete. The process comprises the forming of a slurry of magnesium hydroxide, preferably precipitated from seawater, and water wherein the magnesium hydroxide comprises at least about 25-50% of the slurry by weight, and spraying the slurry onto and along the crown of the concrete pipeline to provide a slurry coating on the crown of the pipeline of about 0.2 inches in thickness so as to provide a relatively long lasting barrier of high pH and thereby prevent acidic corrosion of the pipeline.