Effect of High Alumina Cement on Refractory Castables

In order to obtain early high mechanical strength, ordinary refractory castable tend to have a higher proportion of cement content (10% to 15%, weight ratio), but this also resulted in a series of refractory castable performance decline, the reason is:
1, in order to complete the hydration of cement, mixing excess water (10% ~ 15%) caused by ceramic refractory castable porosity was high, the density decreased.
2, Calcium aluminate hydrate has strong dehydration and recrystallization effect in the middle temperature stage, destroying the structure of the hard spots in the castable, so that the strength of the castable refractory material in the middle temperature phase drops sharply.
3, cementitious binder will be more into the castable, leading to ceramicized refractory castable load softening temperature decreases, thermal shock stability performance deterioration. In view of the poor performance of ordinary refractory castable, the low cement insulating castable is effective to avoid the high temperature performance. The so-called low-cement refractory castables, the cement content of less than 8%, while less than 4% is called ultra-low cement refractory castable. In contrast, the ordinary refractory castable above mentioned shortcomings, are converted into low-cement castable materials advantage. Its structure is dense. Low porosity, high refractoriness, load softening temperature is high, high temperature strength, thermal shock stability. However, due to its low content of cement, resulting in a long condensation time, low early strength in winter and low temperature conditions, especially in the construction of negative. Therefore, in the masonry, to give full attention