Granulated blast furnace slag

C-S-H = poorly crystalline or amorphous calcium silicate hydrate of unspecified composition. Ggbfs = ground granulated blast furnace slag. Hep = hardened cement paste. Pfa = pulverised fuel ash (fly ash). 

Cement Type Description Notation Clinker K % w/w Granulated Blast Furnace Slag S % w/w Pozzolana Silica Fume D % w/w Fly Ash Limestone L % w/w Minor Addition % w/w... 

Nowadays blended cements are normally used, which are obtained by intergrinding or blending Portland cement with particular mineral substances. Among these, those with the addition of pozzolanic materials or ground granulated blast furnace slag are of particular interest with regard to durabihty of reinforced concrete. 

F ie 5.6 Influence of curing on the depth of carbonation for different cement pastes (6 months, 0.03% CO2) of Portland cement and blended cements with fly ash (PFA) and ground granulated blast furnace slag (GGBS) (Bier, from [10])... 

Table 6.2 Examples of stationary diffusion coefficient of chlorides, D, in cement pastes with wjc = 0.5, cured 60 days, made of Portland cement and cement with additions of fly ash (PEA) or ground granulated blast furnace slag (GGBS) [17]...

Figure 6.11 Schematic of the apparent diffusion coefficient for chloride (D,pp) as a function of time and type of cement for Portland cement, 3096 fly ash and 70% granulated blast furnace slag during marine-splash zone exposure, after [22]...

Studies in the early 1970s [16,17] demonstrated that the addition of natural poz-zolana to Portland cement could reduce the chloride diffusion coefficient of concrete by three times. Additions of ground granulated blast furnace slag (GGBS) and fly ash (PFA) have an even more marked effect on the diffusion coefficient... 

M. Joo, Y. Ohama and K. S. Yeon Strength properties of autoclaved and combined wet/dry-cured SBR-modified concretes using ground granulated blast-furnace slag. Magazine of Concrete Research Vol.56, No.9 (2004), pp.513-521. 

Additives and cement replacement materials such as pulverized fuel ash (fly ash), ground granulated blast furnace slag, silica fume (micro silica) and other materials can reduce the pore size and block pores enhancing durability further. However, proper curing may be vital to get the required performance with these blended cements. 

Ground granulated blast furnace slag, microsilica.fly ash... 

The blended cements containing apart of limestone also granulated blast furnace slag reveal good properties [125]. The concrete of this cement show low carbon-ation rate and higher resistance to freezing and thawing, also in the presence of 3 % NaCl solution [125]. 

Many research were focused on the effect of fly ash, siUca fume and granulated blast furnace slag addition on the concrete freeze-thaw resistance. All these additions improve the freeze-thaw resistance, as compared with the concrete from Portland cement, however, on condition that all these eoncretes are air entrainment [80], Freeze-thaw resistance of concrete with fly ash ean be lowered in the case when it has high coal content. The limit value, increased recently to 9% (according to the European standard EN 197-1 2002/A3 2007), is too high and the 5% level should be maintained, as it was reeommended by the elder directives (previous standard EN 197-1 2002). The effeet of non-eombusted coal on the appUcabilily of fly ash is diseussed in details in Seet 7.4. 

---