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Suppose that we have already developed the job mix formula and that well-perform­ing batching devices, a screen deck, balances, and so on are at our disposal. Then we are ready to start production. A common occurrence with starting up an asphalt plant is the instability of the mixture temperature during the first production period. Therefore […]

By and large, the production of an SMA in contemporary asphalt plants does not present particular problems. The following are a few general tips about the production of SMA: • SMA requires some production consistency with no breaks, stoppages, or similar “jerking” of the production process. Any alterations to the type of mixture being produced […]

Having designed and checked the SMA mixture, the time has come to produce it according to the job mix formula (JMF). In this chapter we shall deal with • Requirements for the organization of an asphalt plant • Assumptions and control over the SMA production process • Production of the SMA mixture in a batch […]

Some references to a method consisting of the testing of mortar viscosity and com­paring it with the pure binder viscosity may be found in the literature. By and large, such a comparison would be a stiffening factor. However, as it has been pointed out in Anderson’s work (Anderson, 1987), not only do the filler properties […]

Various methods of testing for an increase in the softening point are used in many countries. For example, in Germany, two methods are applied: the R&B method and Wilhelmi’s method. According to an U. S. review of fillers (Harris and Stuart, 1995), in Germany an acceptable range of AR&B of 10-20°C has been adopted for […]

• Methods of increasing of softening point—ring and ball (R&B) method, according to EN 13179-1 (delta ring and ball), and similar methods • Rigden’s method, according to EN 1097-4, and Rigden-Anderson’s method • The method of increasing mortar viscosity The two European tests cited in EN 13043 (EN 13179-1 and EN 1097-4) are carried out […]

The U. S. method (here called Rigden-Anderson) described in Anderson (1987) stipulates 25 strokes of the 100 g dead weight. Results of the measurements form the basis for calculating the volume of air voids in a dry compacted filler. Only 1.0-1.3 g of filler is needed to conduct the testing. After determining the content of […]

Rigden’s and Rigden-Anderson’s methods apply to any fine material used as a filler in hot mixes (e. g., bag-house fines and added filler). Filler air voids make up an air volume occurring among grains of filler compacted with a special apparatus by a standardized method. Test methods according to the EN standard (Rigden) and the […]

The methods of draindown testing described in this chapter differ in details. Table 8.4 shows the most important differences among them. Table 8.5 depicts commonly adopted assessment criteria of draindown testing results. The following remarks deserve mention: [50] TABLE 8.3 Drain-Off Test Parameters for Schellenberg’s Method according to EN 12697-18 Test three samples of the […]

The U. S. method of mastic draindown testing has been described in the standard AASHTO T 305-97. It is used for porous asphalt mixes (also called open-graded friction course [OGFC]) and SMA mixes. Test parameters are shown in Table 8.2. Samples of the mix are placed in wire baskets (Figure 8.3). For SMA mixes equal […]