Mexican cement and building materials company Cemex SAB (CX, CEMEX.MX) is expected to report modest sales growth for the third quarter but a decline in operating cash flow and a wider net loss compared with a year earlier, as weakness in the US market and the depreciation of the Mexican peso hurt its performance. Cemex had sales of $3.9 billion in the July-September quarter, up from $3.8 billion a year earlier.