The Semi-quantitative Analysis Of C-S-H Gel In Blended Cements

Among the hydration products of ordinary Portland cement(OPC), the amount of calcium silicate hydrate(C-S-H), which is calculated not only from volume but from quantity, is primary. C-S-H has been studied intensively researched by cement researchers, because it has a great effect on cement paste and concretes' macroscopically behaviors. However, most researching work just focus on it's composing, structure and establishing the chemical model, few research work has been carried out to calculate quantity of C-S-H, especially in blended cement. In this article use R.A.Olson water adsorption's method, amended water adsorption's method and calcium hydroxide decoupling's method are adopted to study the semi-quantitative analysis of C-S-H in OPC especially high C3S cement and mixed high actived mineral admixtures in blended cement.By researched disadvantage and advantage of R.A.Olson water adsorption's method, an improved method, including using different Ca/Si ratio of pure C-S-H as standard sample and classifying chemical composing according to the hydrate time and mineral admixtures' effect, has been done based on it. The results demonstrates that the amended water adsorption's method can get more precise result than R.A.Olson water adsorption's method, however, the accuracy of both measures depends on the proportion of high dense C-S-H and low dense C-S-H.The relationship between mineral admixtures' reaction degree and expenditure of calcium hydroxide has been studied, meanwhile a new method for semi-quantitative analysis of C-S-H is acquired. The result based on is closer to theory value. The error of OPC is just about 6%, which in the blend cement at hydrate early, middle and late time are respectively 6%,5%,2%The principle and calculated result according to R.A.Olson water adsorption, amended water adsorption with calcium hydroxide decouplings' method, author find the precise degree is calcium hydroxide decoupling's method, amended water adsorption's method and R.A.Olson water adsorption's method in turn. By analyzed calculated errors, the chemical composing has a great effect on any measures to semi-quantitative analysis of C-S-H. The equation of semi-quantitative analysis of C-S-H in blend cement at different hydrate time was regressed according to the resultof calcium hydroxide decoupling's method, and the changing law of C-S-H in blend cement and the elements effect on this changing was discussed...