Effect of Alcohol Amines on Cement Hydration and Strength Properties
Grinding aids are admixtures that are added during cement grinding to aid in the grinding without compromising human health and cement and concrete properties. Alcohol amines are the main components of cement grinding aids in the industry. The strengthening effect of these substances on cement is mainly reflected in two aspects: First, physical reinforcement, that is, the influence of alcohol amines in the grinding process. The change of strength caused by the grading of cement particles, such as the addition of alcohol amines, under the same specific surface area, the concentration of cement particles is concentrated, thereby increasing the strength of the mortar; the second is the chemical strengthening effect, which is the alkalinity of the alcohol amines. The chemical excitation effect of the mineral hydration process.
In actual production, due to the incomplete research on the chemical strengthening mechanism of various alcohol amines on cement, the combination of alcohol amines in grinding aids is rarely adjusted according to the clinker mineral composition or cement strength, resulting in enhanced grinding aids. The effect is unstable, so it is particularly urgent to study the effects of various alcoholamines on the hydration mechanism and strength properties of different clinker minerals. Triethanolamine promoted the hydration rate at 1d, 3d and 28d age; triisopropanolamine reduced the hydration rate in the early (1d, 3d) and significantly increased the hydration rate at 28d; diethanol monoisopropanolamine, EDIPA has little effect on the early hydration rate, which can significantly increase the hydration rate at 28d age. TIPA, EDIPA and DEIPA increase the chemical combined water content of the complete hydration sample, reduce the proportion of CH in the hydration product, and change the cement. The composition of the hydration product.
The study of the strength of the four alcohol amines for the cement composition of different clinker minerals shows that: 1.TEA mainly increases the early mortar strength of cement, and the early strength of cement with less C3A content and relatively lower early strength increases. Significant. 2. TIPA mainly improves the cement mortar strength in the later stage; and the cement with less C3A content and relatively lower early strength will reduce the early rubber sand strength; 3. DEIPA has a certain enhancement effect on the early and late strength, and the C4AF content The higher strength of the later cement is more pronounced. 4.EDIPA improves the early grit strength of L cement, reduces the early grit strength of F cement, and can significantly improve the late grit strength of cement.
The high-performance grinding aid has good grinding and reinforcing effect on ordinary Portland cement: it improves the grinding fineness of cement; enhances the fluidity of cement; improves the particle size composition and particle distribution of cement, and makes cement particles The average particle size is reduced, the particle size distribution is narrowed, and the fine particle content is increased. The most important thing is to increase the content of the median diameter of 3 to 32 μm; the strength of the cement is increased by 3d and 28d, so that the structure of the cement slurry is denser. The mechanism of action of the grinding aid is mainly to reduce the pulverization resistance, prevent agglomeration and pasting, and improve the fluidity, thereby enhancing the frequency and efficiency of the action of the material and the ball. The reinforcing effect of the grinding aid on the cement is mainly due to the addition of grinding aid. The change in the distribution of cement particles after the agent.