Blog Archives

Plan panel installation

Posted by on 23/ 11/ 15

It’s smart to plan an installation sequence when there are a number of walls to finish with drywall. Determining which walls to cover first, and how panel layout will work, saves time and aggravation. Here are some tips to help you plan the installation sequence for walls:

HANG PANELS HORIZONTALLY. By installing 12-ft. panels horizontally, you greatly reduce the number of joints in a wall. The top panels

should be hung first. Don’t worry if the bot-

*

tom panel doesn’t extend all the way to the subfloor; this small gap will be covered by the baseboard trim. For rooms with 9-ft.-high walls, use 54-in.-wide drywall panels instead of the standard 48-in.-wide panels.

START ON CLOSETS FIRST. Check to see whether there are any closets that must be drywalled before working on long walls...

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EN 12697-12 Method

Posted by on 23/ 11/ 15

This EN 12697-12 method test is conducted on cylindrical specimens prepared in a laboratory (in a gyratory compactor, using a Marshall hammer) or cored from a slab cut out of a pavement. Specimens of 100 ± 3 mm, 150 ± 3 mm, or 160 ± 3 mm in diam­eter may be tested. When testing specimens 100 mm in diameter (compacted using a Marshall hammer, for instance), only mixtures with a gradation not larger than 0/22 mm can be tested. The set of specimens (minimum of six) of an asphalt mixture is divided into two groups. Both groups should be prepared at approximately the same time (within 1 week or less of each other). Half of the specimens are stored without conditioning, while the other half are subjected to conditioning in water...

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AASHTO T 283 Method

Posted by on 23/ 11/ 15

The AASHTO T 283 method involves conducting tests on a comparable set of speci­mens in an original (unconditioned) state and after conditioning and then comparing the results. In some literature this test is also called the modified Lottman test.

Appropriately prepared specimens are divided into two sets. One set is designed for testing without conditioning, while the other is subjected to conditioning in water and freezing. Both the original and conditioned specimens are tested with an indi­rect tension apparatus. The ratio of the conditioned tensile strength to the strength of the original specimens is called tensile strength ratio (TSR). TSR is usually required to be greater than 70% or 80% (most often 80%).

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Modelling Hypotheses

Posted by on 23/ 11/ 15

The pavement was modelled in 3D, considering visco-elastic behaviour for the bi­tuminous material, and the non-linear elastic Boyce model (Eq. 9.10) for the un­bound granular material and the soil. The material parameters for the bituminous layer were determined from complex modulus tests and the in-situ temperature of the bituminous layer was taken into account in the modelling. The parameters for the unbound granular material (UGM) and for the subgrade were determined from repeated load triaxial tests. For the UGM, tests were performed at 3 different wa­ter contents: 2.3%, 3.8% and 4.8%, corresponding to the water content variations observed on the site.

11.4.5.1 Modelling of the Pavement Response for Different Water Contents

A series of calculations was performed for the 3 load level...

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POLE TYPES

Posted by on 23/ 11/ 15

Poles are available in a number of materials. The advantages and disadvantages of each follow.

Steel. Steel poles are available in galvanized, painted, powder-coated, and weathering types, plus a combination of powder coating over galvanizing. Galvanized is the most popular of the steel types because of the comparatively low cost and extended life. Painted poles are used primarily when a color is desired, but they require continual maintenance. The powder coating over galvanizing serves the same purpose and requires little maintenance. Weathering steel poles offer enhanced aesthetics but pro­visions must be made for the rusty runoff.

Aluminum. Aluminum poles are popular because of their resistance to corrosion and the resultant low maintenance cost...

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Rejuvenating

Posted by on 23/ 11/ 15

Подпись: 7. If it's necessary to cut tiles, place them symmetrically on both ends of the sidewall. Though it's possible to cut all partial tiles at once, measuring each ensures a better fit. Подпись: earlier. (This is also a good time to draw plumbed lines at either end of the back wall, indicating where cut tiles begin.) Next, use your story pole on the sidewalls, to see if it's necessary to cut tiles for them and, if so, where to place those tiles. In most layouts, a full column of tiles is placed along the outside edges of sidewalls because they are visually conspicuous; cut tiles are consigned to the corners. But if the back will have no cut tiles, consider putting full tiles in the inside corner of each sidewall. Also draw plumb lines to indicate the outside edges of sidewall tiles. Finally, you may want to draw additional layout lines to subdivide the back wall and anticipate tile cuts around the soap dishes, the tub spouts, the shower mixing valves, and so on. As with floor-tile installations, pros often begin setting tub surrounds in the middle of a tile field, where control lines intersect, setting a quadrant of full tiles at a time, then going back later—often, the next day—to cut and set partial tiles and trim pieces. It's also advisable to leave plastic tile spacers in place till the thinset cures. After pulling out the spacers with needle-nose pliers, you're ready to grout. Grout Joints and Caulking

If your grout is moldy, use a soft-bristle plastic brush to scrub the joints either with household cleaner, a weak bleach solution, or a tile-specific cleaner like Homax® Grout and Tile Cleaner. Wear rubber gloves and goggles, and always brush such solutions away from your face. If the mold returns, try installing a ventilator fan to reduce the moisture in the room. If the grout is intact but dingy, scrub, rinse, and allow it to dry before applying a grout colorant, which will both color and seal the grout. Follow the manufacturer’s instructions.

However, if tiles are loose; if surfaces flex; or if you see water damage around fixtures, at the base of a tub or shower, or along the backsplash of a counter, the substrate has probably deteriorated and should be repla...

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DURABILITY: WATER AND FROST RESISTANCE

Posted by on 23/ 11/ 15

Pavement durability is a broad term. Water and frost resistance of asphalt mix­tures have a disadvantageous effect on the mechanical performance of a course. Undoubtedly, the composition of a mixture—the type of aggregate, gradation of the mix, the type and quantity of binder, the presence of additives and the content of air voids—has an impact on this resistance. More information on this issue may be found in different publications (e. g., Kanitpong and Bahia [2003]; Santucci [2002])

The most common assessment methods for water and frost resistance of asphalt mixtures can be divided into the following two groups:

• Standardized methods

• Method AASHTO T 283

• Method EN 12697-12

• Non-standardized methods (devised in research centers for particular or local use)

A description ...

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Experimental Pavement

Posted by on 23/ 11/ 15

The experimental pavement structure is presented in Fig. 11.11. It had a length of 28 m, a width of 6 m and consisted of:

• a bituminous concrete wearing course, with an average thickness of 85 mm;

• a granular base (0/20 mm crushed gneiss) with an average thickness of 430 mm;

• a subgrade soil consisting of 2.5 m of mica-schist with a low modulus (around 30 MPa).

Asphalt concrete (85 mm)

Fig. 11.11 Structure of the LCPC experimental pavement

The instrumentation installed in this experimental structure included:

• strain gauges to measure longitudinal and transversal strains at the bottom of the asphalt layer;

• displacement transducers to measure vertical strains in the top 100 mm of the granular layer and of the subgrade;

• vertical pressure transducers at the top of the subgra...

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Location of Poles

Posted by on 23/ 11/ 15

The location of a lighting pole is partially dictated by the lighting scheme selected by the designer for a section of roadway. Using the conventional (cobra head) type luminaires requires the pole to be close to the travelway and therefore, unless it is behind a barrier, most likely to be struck by an errant vehicle. A median barrier-mounted pole is less likely to be struck, but occasionally an out-of-control vehicle will get high enough on the barrier to impact the pole. When this occurs, the danger to oncoming traffic will be increased if the pole is of a breakaway design. Because of this possibility, median-mounted poles are normally not designed as a breakaway type...

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ROADSIDE SAFETY

Posted by on 23/ 11/ 15

The primary purpose of roadway illumination is to increase safety by enhancing night­time visibility. The net safety benefit from increased visibility is influenced by the hazard posed by the roadway lighting or luminaire support acting as a fixed object. If roadway illumination is not warranted, or if it is installed wrong, there is a strong pos­sibility that traffic hazards will be increased rather than reduced by providing illumi­nation. The AASHTO publication Roadside Design Guide requires the lighting designer not only to produce an effective, efficient lighting system but also to consider removing the hazards inherent in such a system [13]. The Roadway Design Guide stresses that safety should be enhanced by considering the following, in decreased order of desirability:

• Remove th...

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