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Rigid Pavement Production

Production of cement mixes for rigid pavements involves mixing raw materials and heating them in a kiln to produce cement. The cement can then be mixed with aggregate, water, and admixtures to create ready-mixed concrete.

Figure 3. This photo shows a portion of the 540 ft. long wet process kiln at Lafarge Seattle.

Cement Production

Example Operation – Lafarge Seattle An example operation of cement production is taken from Lafarge Seattle. Below Figures 1 and 2 show the relation of the Lafarge plant to Downtown Seattle and 3D imagery of the Lafarge plant respectively. Overall Lafarge has 20 plants in North America, 16 of which produce portland cements and four … Read more »

Figure 2. Loading PCC for truck mixing.

Truck Mixed PCC

Truck mixed PCC is usually proportioned by batching the separate ingredients directly into the concrete mixing truck.  The ingredients are usually charged in a certain order to ensure good mixing of all ingredients.  Although the specific order depends upon local practice, mixing plant procedures and possibly job specifications, a typical charging order is shown in … Read more »

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Shrink Mixed PCC

Shrink mixed PCC is partially mixed in a plant mixer before discharging into a truck mixer.  The short mixing period in the plant mixer reduces the bulk volume of the overall ingredients by allowing fine aggregate, portland cement and water to fill the large void space in bulk coarse aggregate.  Typically, 1 m3 (1.3 yd3) … Read more »

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PCC Plant Operations

All PCC intended for pavement use is ready-mixed concrete. Ready-mixed concrete refers to PCC that is delivered to the customer in a freshly mixed and unhardened state (NRMCA, 2002). Therefore, PCC production involves the batching and mixing of portland cement, aggregate, water and admixtures to form a ready-mixed concrete in accordance with the approved mix … Read more »

Figure 5. Mobile central mixing plant.

Central Mixed PCC

Central mixed PCC is usually proportioned by batching the separate ingredients into a central plant mixer (see Figures 1 through 4) where they are completely mixed before discharge into a transport vehicle.  Transport vehicles can be concrete mixing trucks or conventional end and bottom dump trucks depending upon travel distance and other requirements.  About 20 percent … Read more »

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