Blaine specific surface

Fig. 4.18 Effect of gypsum on the consistency and w/c of cement paste and concrete (according to [36]) (Blaine specific surface, water content according to ASTM Cl 87)...

Fig. 9.16 EfFeet of fineness of expansive cement type M two components on expansion. (according to [90]). The Blaine specific surface area of Portland cement 1 2,600 cmVg, 2 3,300 cm /g, 3 4,500 cmVg...

Two types of instruments are employed to determine the specific surface area by permea-metry. Those of the first type are called constant pressure systems, and the Fisher subsieve sizer is a typical example that belongs to such systems. Instruments of the second type are known as constant volume permeameters, and the apparatus devised by Blain is an example. 

Blaine (1941) used the Carman method, modified by Lea and Nurse (1939), to determine the specific surface of cement and developed a con-... 

The specific surface area of eement is eommonly determined directly by air. permeability methods. In the Lea and Nurse method (LI 5). a bed of cement / of porosity 0.475 is eontained in a cell through which a stream of air is f passed, and steady flow established. The specific surface area is caleulated ( from the density of the eement, the porosity and dimensions of the bed of j powder, the pressure differenee aeross the bed, and the rate of flow and ] kinematie viscosity of the air. In the Blaine method (B36), a fixed volume of I air passes through the bed at a steadily deereasing rate, whieh is controlled / and measured by the movement of oil in a manometer, the time required i being measured. The apparatus is ealibrated empirically, most obviously / using a cement that has also been examined by the Lea and Nurse method. The two methods gave elosely similar results. The Blaine method, though not absolute, is simpler to operate and automated variants of it have been devised. 

Correlation between specific surface areas measured using a simple and robust technique such as gas permeametry and SSA determined by more sophisticated techniques such as PSD, MIP and BET have been carried out. A good agreement between Sbf (surface measured by gas permeametry, Blaine Fisher, Sbf) and measured Sbet was obtained. This is due to the fact that the DS studied does not exhibit intraparticular microporosity (both Krypton and air can access all the surface developed by the powder). Sbf compared with estimated Sng (estimated from MIP results) and Spsd (estimated from PSD results) show a good linearity, but Shb and Spsd values are overestimated. This arises due to the simplifying approximations for particles shape included in the theoretical models for PSD and PIM... 

Specific surface area (SSA) by gas permeametry Measurements have been carried out using a Blaine Fisher permeabilimeter (95 Sub-Sieve-Sizer). 

The optimmn gypsum content is influenced also by the fineness of cement and the content of alkali. The gypsum addition increases with the specific surface area of cement S (by Blaine method, in m /kg) and with the Na O, content. The following correlation has been proposed by Ost [40] ... 

The fineness of cement may be conveniently characterized by the Blaine method, even though the values obtained by this procedure are systematically lower than those found by the more accurate, but also more complicated, BET method. The specific surface area of ordinary Portland cement typically ranges between 280 and 350 m /kg (Blaine), whereas high early strength cement may be groimd up to a specific surface area of 450-500 m /kg (Blaine). This higher smface area contributes to an accelerated hydration of the cement, but also increases its water requirement. 

Low specific surface area Portland cement is ground to a specific surface area (Blaine) below 300 m /kg or even below 250 m /kg (Blaine) with reduced amounts of calcium sulfate. It is not intended for general use, but for special appUcations in which the presence of fine particles is not desired and their amount should be kept as low as possible. Such appUcations include ... 

The large specific surface area of TLC-cellulose powder (about 15000 cm /g for MN 300 according to Blaine s method) means that more substance can be taken up in a smaller space this leads to compact spots. 

Important methods for the determination of the specific surface area and of the pore size distribution are based on the measurement of the gas adsorption isotherm [1,2]. The gas adsorption method and the evaluation according to Brunauer, Emmett and Teller using the two-parameter BET equation has been standardized in several countries for a number of years and an ISO standard just appeared. To establish the pore size distribution the method of Barrett, Joyner and Halenda (BJH) is generally accepted. Other methods for this purpose make use of the flow resistance of air through the compressed sample. The Blaine test and other flow tests used to characterize building materials are standardized world-wide. 

Permeability. The rate of flow of a fluid (usually air) through a porous ceramic material per unit area and unit pressure gradient. This property gives some idea of the size of the pores in a body -whereas the measurement of porosity (q.v.) evaluates only the total pore volume. From the permeability of a compacted powder the specific surface (q.v.) of the powder can be deduced. B.S. 1902 Pt. 3.9 describes a gas permeability test applicable to refractory materials, as does ASTM C577. The ASTM C866 test for the filtration rate of whiteware clays depends on their water permeability. See blaine test carman equation lea and nurse... 

Rigden s Apparatus. An air-permeability apparatus for the determination of the specific surface of a powder air is forced through a bed of the powder by the pressure of oil displaced from equilibrium in a U-tube. (P. J. Rigden, J. Soc. Chem. Ind., 62,1, 1943.) The apparatus is essentially the same as that used in the blaine test (q.v.). 

The fineness of grinding of cements may be determined by sieving or a separation method (the fineness being expressed as a certain percentage by weight above a certain size, e. g., as residue retained on a standard sieve), but is more usually based on the specific surface determined by the Blaine method (air permeability of a bed of cement, the result being expressed in cm /g the finer the cement, the higher the specific surface) (see also Section X.1). 

Blaine air permeability testing apparatus (ASTM C 204-51) for determining the specific surface of powders, with permeability cell made of stainless steel, mounted on lacquered rough-service steel plate, with suction fan, filling funnel, 1 set of filter papers, 1 bottle of oil and 1 thermometer graduated in 0.1 C. calibration sand (approx. lOOg), officially certified ... 

Blaine air permeability testing apparatus (ASTM C 204-51) for determining the specific surface of powders, complete, calibration sand (approx. lOOg), officially certified ... 

Specific Surface Area Sneeifie surface area of iron ore is measured by Blaine method (GB8074-87), the test is done in Blaine breathable instrument [7, 8]. 

GB/T 8074-1987.Testing Method for Specific Surface of Cement—Blaine Method. 

Figure 10.13 Comparison of SSAs determined by the Blaine test and the nitrogen adsorption technique. (Data from Arvaniti, E. C. et al., Materials and Structures, 1-15, 2014a Mantellato, S. et al.. Impact of sample preparation on the specific surface area of synthetic ettringite. In preparation, 2015b.)...

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