Precast concrete pipe

Sealing between precast concrete pipes and culverts... 

EXHIBIT 11-25 Precast Concrete Pipe Rack Considerations... 

Type I (Normal). This is the general purpose Pordand cement used for all appHcations where special properties are not needed. Common appHcations include concretes for paving, building doors, roof decks, reinforced concrete buildings, pipes, tanks, bridges, and other precast concrete products. In 1989 Type I and Type II accounted for over 92% of the Pordand cement produced in U.S. plants. Exact data are not available that separate Type I and Type II Pordand cement, but it can be assumed that Type I production was much greater than Type II. 

Concrete masonry is simply the name given to the cement building blocks employed in the construction of many homes, and it is simply a precast block of cement, usually with lots of voids. Precast concrete is concrete that is cast and hardened before it is taken to the site of construction. Concrete sewer pipe, wall panels, beams, grinders, and spillways are all examples of precast cements. 

Fig. 8-5. Commonly used piles, (a) Precast concrete (b) Raymond cast-in-place pile (may have spread footing by ramming concrete) (c) steel pipe pile (may have spread footing by ramming concrete) (d) steel P-bcam pile (e) wood (/) steel sheet piling.

A vented ford is one of LWSCs that has pipe(s) imder the crossing that accommodate low flows without overtopping the road. High water will periodically flow over the crossing. The pipe(s) or culverts maybe embedded in earth fill, aggregate, riprap, or Portland cement concrete. Corrugated metal, plastic and precast concrete are commonly used materials for pipes in vented fords... 

Structural materials—Materials for foundations can be timber, precast concrete, cast-in-place concrete, compacted dry concrete, grouted concrete, posttension steel, H-beam steel, steel pipe, composite, etc. 

Ground effect—Depending on disturbance to the surrounding ground, piles can be displacement piles, low displacement, or nondisplacement piles. Driven precast concrete piles and steel pipes with end plugs are displacement piles, H-beam and umplugged steel pipes are low-displacement piles, and drilled shafts are nondisplacement piles. 

N-3 Septic Tank. The 124-N-3 septic system Is a cesspool that served the 107-N building from 1982 to the present. The unit served two to three employees working at the 107-N building, as well as temporary construction workers In the area, and was designed to receive only sanitary sewage. The cesspool Includes a 1,900-L (500-gal) precast concrete tank, perforated tile pipe, and solid cover with 0.6 m (2 ft) of crushed stone below the tank. The estimated dally flow was 170 L/day (45 gal/day) (DOE-RL 1990). 

The plant layout designer should be aware that pre- ast concrete pipe racks require structural members hat are mudi larger than most designs. Exhibit 11-25 llustrates a precast column with an embedded steel... 

Sewer boxes should be made of precast reinforced concrete pipe a minimum of 48 in (1,220 mm) in diameter. The system engineer establishes the need for sealed sewer boxes. Those containing clean storm or fire water do not require sealing, but toxic hydro-. carbon-bearing run-off requires a sealed sewer box that is vented to a safe location, as shown in Exhibit... 

Hot Melt, Field-Extruded Sealants. Several butyl raw material manufacturers and sealant producers have recently developed butyl tapes. These are premasticated, high viscosity thermoplastic compositions that are fed as talced ribbons into a polymeric sealant applicator (PSA). Within the PSA, the compound is heated and extruded into the joint opening to form a smooth joint that cools rapidly with excellent adhesion claimed, even to oily or otherwise poorly prepared surfaces. These hot-applied, post-formed butyl tapes have been successfully used to seal insulated glass units, automotive windshields (Fig. 4), curtain walls, concrete pipes, precast concrete structural joints, and as bedding compounds in combi-... 

Formed insulation products - Medium- to fine-grained expanded perhte is incorporated into pipe insulation, insulation boards, acoustical ceiling tiles, precast concrete floor and roofing tiles, and precast roof decks. The perlite contributes to reduced weight, acoustical and thermal insulation, and fire... 

S.I.L. uses standard concrete transit mixer trucks modified to provide gas or propane heat to the mix drum to prepare mixes for both precast and poured-in-place work. Since 1977 several poured-in-place field trials have been completed and numerous projects in the Calgary area have now been constructed. Precast products that have been marketed include parking curbs, pipeline weights, sewer pipe, median barriers, and sidewalk slabs. 

Greater consideration could be given during the design process to the removability of all plant and piping systems. This, combined with the greater use of unit construction techniques such as precast, bolted concrete elements, structural masonry or bolted structural steelwork connections, would allow better access to be established for plant and equipment removal. 

Precast Elements There are numerous applications of precast polymer concrete such as panels, pipes, drainage channels, tiles, bricks, linings, manhole structures, stair treads, electric insulators, etc. [11, 15]. 

---