India is still in the "dark ages' in concrete technology and lacked trained and well-equipped technical manpower to give practical shape to the Rs 70,000 crore initiative taken by the Vajpayee government for infrastructure development, feels Dr P.K. Mehta, Prof emeritus, University of California. Referring to advancements in concrete technology he said blending flyash with cement increased the strength and durability of the binding material. High volume flyash cement (with equal ration of cement and flyash) was being widely used in countries like Holland, China and Japan.Use of flyash reduced carbon dioxide emissions in cement and also helped check pollution from thermal plants. It was an environment-friendly material.