Materials. - Common brick shall be clay or shale brick, sound, hard, thoroughly and evenly burned, of close texture, uniform in shape and size, and free from warps, cracks, or other defects. Dried brick broken in two and immersed in water for twenty-four (24) hours shall show an increase of not less than two (2) per cent. nor more than twelve (12) per cent. of the dry weight.

Vitrified brick shall be clay or shale brick, smooth, sound, hard, tough, of close texture, vitrified throughout, uniform in shape and size, with sharp edge9 and free from warps, cracks, and other defects. Dried brick broken in two and immersed in water for twenty-four (24) hours shall not show an increase of more than two (2) per cent. of the dry weight.

Mortar, unless otherwise specified, shall be made of one part by measure of Portland Cement and two and one-half (2 1/2) parts clean, coarse sand with sufficient water, well mixed to make a stiff paste. The cement must conform to the requirements specified under Items 30, 31, 32. All mortar must be mixed in suitable water-tight boxes. Retempering or mixing additional water with mortar which has partially set will not be permitted.

Unless otherwise specified on the drawings, brick masonry shall consist of common brick. The brick shall be wetted, freed from dirt and frost, and laid truly horizontal with close mortar-filled "push" joints. Care shall be taken to "break" joints and to thoroughly bond the work. The use of bats, except to effect closures or fill interstices, is prohibited.

Brick masonry shall not be laid in water, nor shall water be permitted to come in contact with such work until the masonry shall have set hard. It shall be protected from the weather and all disturbance, and kept well moistened until set hard.

In bonding new masonry to old, the old brick work shall be toothed and surfaces cleaned of dirt, grease and surplus mortar. In leaving unfinished work for the day, the masonry shall be racked back and left clear of surplus mortar.

Joints for exposed faces shall not exceed one-quarter (1/4) inch in width and shall be carefully pointed except where the surfaces are to be plastered or unless herein otherwise specified.

Surfaces of brick masonry which are to be plastered shall be thoroughly cleaned and wetted, Plaster shall be applied before the masonry has set, and shall receive a smooth, dense trowel finish.

Forms or centers shall be true to dimensions, clean, rigid, and braced to prevent deflection. The details of construction of the forms and bracing shall be such as to insure removal without jar or injury to the brick masonry and to offer to the workmen adequate space in which to lay up the brick work.

Forms or centers shall be left in place until removal is permitted by the Engineer.

Within a range of temperature of from 20° F. to 32° F., brick masonry may be placed, provided the materials be satisfactorily heated and the masonry kept warm and protected in a manner acceptable to the Engineer. When the temperature falls below 20° F. the laying of brick will not be permitted under any conditions.

Measurements. - Payments will be made for the masonry actually placed in accordance with the lines shown on the drawings or as established by the Engineer.

Payment. - The price bid for this item shall include the furnishing of all labor and materials, all excavating, sheeting and bracing, draining, the furnishing and placing of vitrified brick where required, backfilling, embankment, and cleaning up. Work called for under this item includes all brick masonry not specifically mentioned as paid for under other items.