Concrete Block Machines

CONCRETE BLOCK MACHINES.

Concrete blocks in various forms are coming to be recognized more and more as an important factor in building construction. There are com paratively few buildings erected to-day into the construction of which concrete moulded shapes, in some form or other, do not enter. Even where the building is not by any means to be classed as a block structure, we find these shapes commonly used in certain special locations. Their strength and fireproof qualities, their durability under abrasion and severe climatic conditions, their adaptability to harmonious combination with other structural materials, together with their cheapness of cost, have com mended them to very common acceptance for use as water-tables and belt-courses, door and win dow sills and lintels, etc.—for which uses they have very largely supplanted the old-time cut stone.

In ornamental shapes for garden, lawn, and landscape decoration; as columns, capitals, pilas ters, brackets, etc., for the exterior and interior embellishment even of the most elaborate struc tures, they are also coming into more and more extensive use.

The question of their complete function and limitations in building construction, as in the erection of houses built entirely of blocks, is one on which opinions differ considerably. The once common complaint of dampness and con sequent discomfort and unhealthfulness as char acteristic of the block structure, had its basis in the imperfect work that marked the early, un fortunate attempts at this form of construction. But with up-to-date, improved machinery for making blocks, with our present advanced knowledge of the essential requirements in pro portioning and mixing ingredients and in mould ing and curing, and with modern methods avail able for rendering all concrete work as truly damp-proof and waterproof as work in any other material can possibly be made, there is no longer any foundation for this complaint.

There is, moreover, no doubt that with the honest avoidance of all mere attempts at imi tation, with the use of appropriate faces and finishes, with due consideration of the possibili ties of pleasing combination with other mate rials and of harmonious adaptation to surround ings in the selection of attractive outlines and color schemes, concrete blocks do lend them selves admirably to truly artistic effects in building design.

Blocks may be made solid or hollow. Some typical methods of using them in house building are illustrated in Figs. 24 and 25. In wall con struction, solid blocks are laid in single courses for veneering, being bonded to the framework, the interior of the wall being furred, lathed, and plastered. Where the wall is built entirely of concrete blocks, these, if solid, are laid in two courses, with an intervening air-space for insula tion against cold and dampness, the two courses being bonded together either with metal ties or by the use of bonding headers or by means of concrete lugs on the blocks. With the hol low block, on the other hand, the insulating air space is directly provided in the interior of the block itself; and in such cases, if proper care has been taken in the manufacture and laying of the blocks, or in the use of a reliable water proofing process, or in both, furring and lathing may be dispensed with, and the plaster applied directly to the inner surface of the wall.

Hollow blocks are sometimes distinguished as one-piece blocks and two-piece blocks. In the "one-piece" type, the air-space represents the void that was occupied by the core around which the block was moulded. In the "two piece" type, the insulating dead air-space may be obtained by embedding pieces of metal in the block itself to tie together the outer and inner portions, as in the "Anchor" block illustrated in Plate 24 (lower right figure) ; or it may be formed through the shape of the pieces them selves, which, in different commercial types of blocks, are made in a variety of forms resem bling more or less closely in section the steel shapes known as channels, angles, and tees, as in the "Ferguson," "Thomas," and other sys tems (see Fig. 25).