This lecture explores the kinetics of the main hydration peak in cement, discussing the heat evolution, nucleation, growth, and diffusion processes. Various models and hypotheses are presented, including Avrami's equation, the uic model, and the needle growth model. The impact of ions, such as Zn and Mg, on heat evolution is also examined, along with the growth of needles and the formation of C-S-H. The instructor emphasizes the need for quantitative testing of theories and the importance of considering a wide range of variables in understanding the hydration process.