What are the considerations for concrete pumping and placement?

Concrete pumping requires proper mix design: adequate fines content (minimum 300 kg/m3 powder), rounded aggregates preferred, suitable slump (100-150mm), and no segregation. Pump line considerations include pipe diameter (typically 100-150mm), horizontal equivalent lengths for bends and elevation, and maximum aggregate size (1/3 pipe diameter). Pumping pressure depends on mix, distance, and elevation. Initial priming with mortar is required. Re-tempering water must be controlled to maintain w/c ratio.