Control traffic passing near, in, or around work zones. Clean or prepare construction sites to eliminate possible hazards. Signal equipment operators to facilitate alignment, movement, or adjustment of machinery, equipment, or materials. Read plans, instructions, or specifications to determine work activities. Load, unload, or identify building materials, machinery, or tools, distributing them to the appropriate locations, according to project plans or specifications. Measure, mark, or record openings or distances to layout areas where construction work will be performed. Dig ditches or trenches, backfill excavations, or compact and level earth to grade specifications, using picks, shovels, pneumatic tampers, or rakes. Mix, pour, or spread concrete, using portable cement mixers. Tend pumps, compressors, or generators to provide power for tools, machinery, or equipment or to heat or move materials, such as asphalt. Erect or dismantle scaffolding, shoring, braces, traffic barricades, ramps, or other temporary structures. Provide assistance to craft workers, such as carpenters, plasterers, or masons. Lubricate, clean, or repair machinery, equipment, or tools. Position or dismantle forms for pouring concrete, using saws, hammers, nails, or bolts. Smooth or finish freshly poured cement or concrete, using floats, trowels, screeds, or powered cement finishing tools. Operate jackhammers or drills to break up concrete or pavement. Apply weather-stripping to reduce energy loss.