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Chapter 3 Cement. § 3.3 Portland Cement With Mineral Materials. Mineral Admixture Ordinary Portland Cement (P.O) Portland granulated Blast-furnance-slag Cement (P.S) Portland-Pozzlana Cement (P.P) Portland fly-ash cement (P.F) Composite Portland Cement (P.C). granulated blast-furnance slag.
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Chapter 3 Cement §3.3 Portland Cement With Mineral Materials • Mineral Admixture • Ordinary Portland Cement (P.O) • Portland granulated Blast-furnance-slag Cement (P.S) • Portland-Pozzlana Cement (P.P) • Portland fly-ash cement (P.F) • Composite Portland Cement (P.C)
granulated blast-furnance slag P.S Grinding Hydraulic cementing material Clinker Gypsum What is Portland granulated blast-furnance slag Cement • It refers to the cement which is formed by Cement clinker, granulated blast-furnance slag and a little gypsum • Quantities of granulated blast-furnance slag is 20%~70%
Technical Properties • Its property is different from Portland cement and ordinary cement • Reasons: In cement, Portland cement and ordinary cement is more and the clinker is little • Technical performance: It can be divided into 6 types:32.5, 32.5R, 42.5, 42.5R, 52.5, 52. 5R • Its early hardening is low • Other technical requirements are the same with Portland cement
Strength grade Compression strength (MPa) Fracture strength(MPa) 3d 28d 3d 28d 32.5 32.5R 42.5 42.5R 52.5 52.5R 10.0 15.0 15.0 19.0 21.0 23.0 32.5 32.5 42.5 42.5 52.5 52.5 2.5 3.5 3.5 4.0 4.0 4.5 5.5 5.5 6.5 6.5 7.0 7.0 Tab.3.3.2 Strength Demands of P.S,P.P,P.F
Characteristics of P.S Comparing to Portland Cement and Ordinary Cement • Strength is low in the early days and high in the later days • The hydration of slag cement takes 2 steps: • hydration of cement clinker; secondary hydration reaction. • In the early days of a secondary hydration, the strength is low with low speed and little hydration. But it is contrary to the later days. • It is applicable to the prefabricated member cured in the middle days and projects with bearing slowly. • But it is not applicable to the projects with the requirement for higher early hardening.
Characteristics of P.S • Strong anti-corrosion and poor carbonation resistance • It is applicable to the water concrete and marine concrete • Not used in house with high concentration of CO2 • Because of the low content of calcium hydroxide. • Low hydration heat • It is applicable to the project with mass concrete
Characteristics of P.S • Temperature sensitivity • It is applicable to the high temperature cuing because of temperature sensitivity. • Low anti-freezing • The early hardening is low . • Water requirement of volcanic ash is big. • Heat resistance • It is applicable to the project with requirement of heat resistance concrete.
Characteristics of P.S • Poor permeability • The large quality of mixing materials result in sharp arris of blast-furance slag and low water requirement and retentivity; therefore it can form bleeding channels easily. • Note: the latter 2 items are the features of P.S. and other properties same with PP、PF cement.