Optimum heat treatment cycle for cements of different type and composition

Strength development of concrete is slow with respect to the impressive imp rovements associated with rapid and serial production of concrete in constr uction technology in recent years. In this respect, the necessity of having concrete reach a desired strength level by accelerating its hardening proc ess in as short a time as possible is inevitable. Various methods have been developed and applied to accomplish this purpose. Heat treatment has an ex tensive application amongst these procedures. Cement as a binder has a grea t importance in heat treatment application due to its function in providing concrete with hardening and gaining strength. The primary factors determin ing the behaviour of cements subjected to heat treatment are fineness and c omposition of Portland cements, the type and amount of additive used in ble nded cements, and cycle parameters. The technical and economical success of heat treatment application depends on the objective and application of a s uitable heat treatment cycle. In this context, heat treatment parameters fo r five cements of different type and composition, which are commonly produc ed in most countries, were determined. It is concluded that a treatment tem perature of 80 degrees C and a 4-hour initial curing before heat treatment is essential as well as reasonable for optimum heat treatment application t o the cements investigated. (C) 1998 Elsevier Science Ltd.