INFLUENCE OF MICROWAVE ENERGY AND REINFORCING STEEL EMBEDDED ON THE CHARACTERISTICS OF CEMENT PASTES WITH VARYING WATER-CEMENT RATIOS

Abstract

This research presented a comprehensive study on the interaction between steel-reinforced cement paste and microwave energy using a single-mode rectangular waveguide. The mechanisms of changes in the adaptive dielectric properties of reinforced cement pastes to predict how these properties are altered when microwave energy were investigated. The structural characteristics of microwave-cured cement paste will be identified. The obtained results show that dielectric properties are relatively high and remain constant during the dormant period. After this period, the hydration reaction resumes and dielectric properties decrease rapidly. Further with the use of microwave heating, the temperature increased monotonically among the positions of measurement during the microwave-curing process. The typical micrographs of the microwave-cured paste at the age of 4 hours after mixing, 28 days after curing in lime-saturated deionized water, and when subjected to microwave energy showed that the samples consisted of hydrated phases and pores, as well as cores of Ca(OH)₂ dendrite crystals, calcium silicate hydrate (C-S–H), and granular structure.