Binder content

The shell-molding process, introduced in the United States in 1948, is an important market for phenoHc resins. In the original process, dry sand and powdered resin (6—8%) are blended. However, because of the high binder content and the difficulty in obtaining a uniform mix, precoating methods were developed. 

Fig. 8. Variation with percent Co binder content for cemented WC grades of (a) hardness, where the numbers represent carbide grain size in pm (b)...

The exact properties depend upon the materials used, grain size, binder content, volume fraction of each constituent, and processing method. 

The flow behaviour of aqueous coating dispersions, because of their high pigment and binder content, is often complex. They have viscosities which are not independent of the shear rate and are therefore non-Newtonian. Shear thickening (when the viscosity of the dispersion increases with shear rate) and shear thinning or pseudoplastic behaviour (when the viscosity decreases with shear rate), may... 

With binder content held constant, an increase in aluminum content is obtained at the expense of ammonium perchlorate content. Since aluminum has a greater density (2.70 gm./cu. cm.) than ammonium perchlorate (1.95 gm./cu. cm.), this exchange can greatly increase the fluidity of the mixed propellant, particularly if the aluminum which is used is spherical or spheroidal in contrast to the shape of ground ammonium perchlorate. 

Binder Different binders have different binding properties and the concentration of an individual binder may have to be changed to obtain similar binding of primary particles. Thus, the type of binder, and binder content in the formulation and concentration of the binder have major influence on granule properties. These properties include friability, flow, bulk density, porosity, and size distribution. 

The VMA appears to indicate the approximate volume of binder required for a mix. Increasing or decreasing the binder content did not produce a consistent variation of strength. 

Probably the most detailed treatment of mix design and construction procedures was developed in a state-of-the-art guideline manual by The Bureau of Mines [44] under the sponsorship of FHWA and the cooperation of The Sulphur Institute. This manual deals with all technologies currently in use in the preparation of SEA binders. The authors propose the following formula for establishing the Equivalent SEA Binder Content to replace, on an equal volume basis, the asphalt in a conventional asphaltic concrete mix design ... 

An approximate of the equivalent SEA binder content provided by Equation (1) is given by... 

The optimum or minimum allowable substitution ratio is then established by means of a series of justification tests at different binder contents. Figure 15 shows a comparison between the Marshall design properties of a conventional mixture using an asphalt binder and a 30 70 SEA binder. As indicated the optimum substitution ratio based on the maximum stability and equivalent air voids is about 1.7 1. Since minimizing the substitution ratio has a direct impact on the economic benefits to be realized by replacing the asphalt with sulfur these justification tests are to be recommended in all mix designs. 

Based on the above, the determination of the optimum binder content for SEA concrete mixtures can be summarized as follows ... 

Establish optimum binder content for a conventional asphaltic concrete mix. 

Calculate the Equivalent SEA Binder content using the formula given above. 

Using the results of steps 1 and 2 above as the maximum and minimum binder contents prepare mixes at a number of intermediate levels. 

Perform justification tests as shown in Figure 15 and select the optimum binder content. 

Once the binder content has been established, the preparation and placement of the SEA mixtures is accomplished using conventional construction procedures. 

The properties are consistent with those suggested by the Asphalt Institute [48] for light, medium and heavy traffic categories, except in the area of air void content, which can be adjusted through changes in aggregate grading and binder content. At S/A... 

Table V presents the "optimum" binder content for the Sulphlex-233 and the AC-20 asphalt cement and selected mixture properties obtained at these optimum values.

Optimum Marshall Binder Contents Sulphlex-233 and AC-20 Asphalt Cement With a Well-Graded Diabase Aggregate... 

The construction was accomplished by SWRI on a low-volume road at its San Antonio facility in December, 1979. The total pavement is 645 feet (197 m) long, 24 feet (7.3m) wide, and includes ten Sulphlex sections in addition to portland cement concrete and an asphaltic concrete control sections. Three different Sulphlex binders, numbers -233, -126, and -230, were employed in the construction besides the binder type, variables include the binder content, the pavement thickness, and the number of lifts used in the construction. 

This combination yields a well-graded blend, and is similar to the aggregate gradation used locally in asphaltic concrete and used in the 1978 SWRI construction. The mix design yielded a binder content of 7.3 percent by weight as most satisfactory. 

In order to assess the effect of binder content variation on performance, three sections with binder contents of 7.0, 7.5 and... 

Packing density (for solid expls) 2) Expl column diameter or confinement 3) Chemical nature 4) Particle size 5) Binder content (in the 5 to 20% range obviously a 20+% binder content can exert a very strong effect and could cause failure) 6) Strength of initiation (primarily in liq expls, where weak initiation can produce a quasi-stable low velocity detonation in solid expls the strength of the initiator may affect run-up distance to stable detonation or even fail to initiate stable detonation)... 

De Longueville et al (Ref 28) also examined the interaction effects of binder content and charge diameter. The test material in each case was 72% by volume of a fixed perticle size RDX with 5 different binders. Max values of D are shown in Table 9, and D vs 1/d plots for mixts 3 and 5 of Table 9 are given in Fig 10. Note that Si content in the binder reduces D... 

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