Optimizing the Sulphates Content of Cemen tUsing Multivariable Modelling and Uncertainty Analysis
This study aims at determining the effect of the cement composition and mortar age on the optimum content of sulphates using maximization of compressive strength as a criterion. Extensive experimentation has been performed to achieve this purpose by utilizing four cement types and measuring the strength at ages ranging from 2 days up to 63 months. Strength is correlated with the ratio of sulphates to clinker content, SO3/CL and moles SO3/ moles C3A. A generalized model correlating SO3, cement composition and curing time is developed, intensely indicating the necessity of placing the SO3 target within the optimum region and realizing it as well. The set of four equations involves polynomial and logarithmic equations correlating the variables. A variance analysis based on error propagation technique, proves that SO3 affects not only average value of strength but also its variability.
Investigation of Some Basic Parameters Affecting the Optimum Sulfates Content of Cement
The present study aims to determine the effect of the cement composition and mortar age on the optimum content of sulfates using as criterion the maximization of compressive strength. Extensive experimentation have been performed to achieve this purpose by utilizing four cement types and measuring the strength at ages ranging from 2 days up to 63 months. Compressive strength is correlated with the ratio of sulfates to the clinker content, %SO3/Cl. For three cement types not containing fly ash, a common region of the optimum %SO3/Cl is determined while when fly ash constitutes a main compound, sulfates optimum is found in a distinguishable region. A logarithmic function describes adequately the relation between optimum and age of the mortar constituting a useful tool in case the strength has to be maximized in a specific age. Key-Words: Sulfates, Strength, Cement, Optimization, Clinker
Effect of added gypsum on compressive strength of portland cement clinker
Etude de l'influence d'addition de gypse sur la resistance a la compression de clinker de ciment Portland sur des compacts de porosite initiale de 28,8 a 34,4% prepares a partir du meme clinker avec ou sans addition de gypse. L'addition de gypse ameliore la resistance du ciment, surtout aux premiers âges de 1 a 3 jours. On montre que cette amelioration est due a l'augmentation de la densite moyenne des produits d'hydratation formes en presence de gypse