Masonry Magazine June 1977 Page. 16
Figure 3
Rectangular units should be laid in a herringbone pattern to prevent "creep" under traffic, permitted by the opening of joints. Interlocking units may be laid in running or stretcher bond as their interlocking design resists the forces that cause "creep," Fig. 3. Each block is placed against the adjacent units without disturbing the sand or other units, Fig. 4 (Developments are taking place at this time relative to mechanized placement of individual units or clusters of block that are tied together with break-away webs.) The order of laying should be such that it is never necessary to force a block between those already laid.
Figure 5
Where whole units do not fit at the edges of a pavement, cut block are used to fill the spaces, Fig. 5. Spaces left around manholes and drainage inlets are treated in the same manner. This is readily accomplished with a small hydraulic block splitter. Spaces less than about 1-5/8" (40mm) can be filled with a sand-cement mortar not leaner than 4:1.
After enough area is laid to make vibration worthwhile, the block are vibrated to their final level with a plate vibrator, Fig. 6. The vibrating action compacts the sand and also forces some sand up between the joints. After the initial vibration, sand is brushed over the surface and is vibrated into the joints by an additional two or three passes of the vibrator. This locks the block together so that they no longer act as individual units but as a group in distributing loads. Vibration also evens out any minor variations in level between units. The vibrator should not be passed closer than about one yard or meter from an unrestrained edge. After surplus sand is removed the pavement is completed and ready for traffic. If heavy trucks are used to deliver materials close to the work, the sanding and vibration should be done before the trucks are permitted to enter that section of the pavement, Fig. 7.
Photographs are from Cement and Concrete Association, Wexham Springs, Slough SL3 65L, England.
Figure 6
NATIONAL CONCRETE MASONRY ASSOCIATION
P.O. Box 135, McLean, Virginia 22101
Figure 7