Sulphate resisting Portland cements

SURYVANSHI, A. K., SCANTLEBURY, J. D. LYON, S. B. 1995. The binding of chloride ions by sulphate resistant portland cement. Cement and Concrete Research, 25, 581-592. 

Destructive expansion from reaction with sulphates can occur not only if the latter are present in excessive proportion in the cement, but also from attack on concrete by sulphate solutions. The reaction involves the Al,0,-containing phases in the hardened cement, and in sulphate-resisting Portland cements, its effects are reduced by decreasing the proportion of the aluminate phase, sometimes to zero. This is achieved by decreasing the ratio of AljOj to Fe203 in the raw materials. In the USA, sulphate-resisting Portland cements are called Type V cements. 

Sulphate-resisting Portland cements have relatively high ratios of iron to aluminium, and the ferrite phase cannot have the composition given above if it contains most of the iron. Tables 1.2 and 1.3 include a tentative composition and atomic ratios corresponding to it, based on scanty data for the interstitial material as a whole (G3,G4) and the requirement of reasonable site occupancies. 

Any attempt to understand the expansive process must thus consider the manner in which the deposition of the products affects the microstructure. The production of ettringite can cause expansion, but does not necessarily do so in a supersulphated cement (Section 9.2.9), much ettringite is formed, but there is no marked expansion. Comparable amounts of ettringite are reported to be formed when ordinary or sulphate-resisting Portland cements... 

Only for cements with low heat of hydration and/or high sulphate resistance Portland cement, Eisen portland cement, Hochofen cement and trass cement with slow early hardening behaviour are additionally given the symbol L, while the symbol F is added to cements with high early strength... 

SRC Sulphate-Resisting Portland Cement/Portlandzement mit hohem Sulfatwiderstand... 

WiELAND, E., Tits, J., Spieler, P. Dobler, J-P. 1998. Interaction of Eu(III) and Th(IV) with sulphate-resisting Portland cement. Materials Research Society Symposium Proceedings, 506, 573-578. 

Clinker can be replaced by Portland cement, all kinds of cement with additions can be also produced in subclass with air entraining agent, additionally the variety resistant to sulphates and limited heat of hydration can also be produced. 

In reality the mechanism of concrete deterioration as a consequence of acid corrosion, if it is sulphuric acid, is the same as in case of sulphate corrosion. For this reason in both environments the matrix based on Portland cement with reduced Cj A content is more resistant. This example shows the imperfection of kind of corrosion classification, presented above. 

Chloroaluminates Chemical compounds formed in concrete when chlorides combine with the C A in the hardened cement paste. These chlorides are no longer available to cause corrosion. Sulphate resisting cements have a low C A content and are more prone to chloride induced corrosion than normal Portland cement based concretes. 

Sulphate-resisting Cement. A portland cement specially made to resist exposure to water containing dissolved sulphates. The chief difference between this cement and ordinary portland cement is that the former has a low tricalcium aluminate content B.S. 4027 stipulates 3.5 % (See... 

Mortars and concretes made with high alumina cement are resistant against sulphate attack and also are better at resisting CO2 from ordinary drinking or mineral water. In comparison, the resistance against alkalis is lower than that of Portland cements. 

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