The science and art of the manufacture of Portland cement : with observations on some of its constructive applications

Front matter

THE

SCIENCE AND ART

OF THE MANUFACTURE OF

Preface

During the last ten years great progress has been made in the knowledge of Portland Cement, and its use has in consequence been extended in a remarkable degree. Engineering works, more especially in the direction of docks and harbours, have given an impetus to its application, securing for it a position of unchallenged importance. This increasing appreciation of its valuable constructive properties has secured a more reliable quality, which the manufacturers are now ambitious to maintain. Since 1868, when my book on the manufacture of Portland Cement was published, the production of Cement has more than doubled in the London district alone.

This gratifying increase, and the accompanying prosperity of the Cement-maker, has not yet led to much improvement in the processes of manufacture, so as to cheapen its cost or render it more acceptable to the consumer. In Germany a more healthy feeling prevails, and no effort is wanting on the part of the manufacturers of Portland Cement to extend the range of its usefulness by the adoption of the best and latest improvements which technical skill can devise. In furtherance of this object the mutual co-operation of makers and users is secured with such profitable results as a confiding interchange of ideas must command. The first fruit of such a combination has resulted in the establishment of uniform testing on a basis sound enough to secure accurate returns, controlled by the best available scientific guidance. When by the process of evolution or some other force of vi

PKEFACE.

" natural development" such a position is reached in England, all concerned will then be able to repose in a haven of comfort, sheltered from the storm of amateur experimenters and their bewildering creations.

I have in the following pages, from the best available sources, discussed the question of Portland Cement-making in its numerous and varied bearings. Its geological aspect has been freely noticed, with the object of removing the erroneous impression or belief that Portland Cement is only obtainable from a combination of chalk and river clays. The prominence given to that division of my argument will, I hope, direct serious attention to the easy production of Cement from sources hitherto regarded as quite incapable of furnishing the necessary materials for its successful fabri" cation. The treatment of these more obdurate materials naturally involves the use of machines differing widely in character from the wash-mill of the " chalk and clay " process. The machinery of reduction required for this purpose has therefore been noticed at some length, and the various machines and their characteristics reviewed and illustrated.

I have discussed the question of Cement-burning in its purely scientific direction, and compared some of the more familiar methods, with an examination of the various kilns, and their leading features and character.

Cement-testing, and the machines used for that purpose, have been referred to at considerable length, but not, in my opinion, more fully than the importance of the subject requires. If the observations on, and review, of the Cement experiments should seem to some of my readers hypercritical, I would plead that being in a great measure responsible for the original adoption of the " Board of Works' " test, I am anxious, if possible, to arrest its reaching a point where reason or common sense cannot follow. If this tendency of aiming at the ideal and impracticable continues unchecked,

PKEFACE.

Vll the eventual result will be a refusal to be controlled by an ever restless and changing system, the ultimate limits of which admit of no reasonable estimation.

Although noticing generally some of the numerous applications of Concrete, I have more particularly referred to the latest outcome of this material in its useful adaptation to paving and sewering. The progress already and so speedily made in this direction, in which all are so intimately concerned, indicates that even now we are still far distant from the ultimate usefulness of which it is capable. In this work, which treats more directly of the Cement, on the quality of which so much of the excellence of Concrete depends, it is impossible to notice at great length the numerous purposes to which it is applied. However, I intend shortly to follow up the subject in a work specially devoted to the consideration of Concrete construction in all its varied and interesting developments.

In a work of this character it would be mere affectation to pretend that its matter and details are altogether original. On the contrary, I am much indebted to many authorities for analyses and other information of the most valuable kind. When such extracts have been used I have, where it was necessary, acknowledged the source of their origin, not so much from the proper desire to record my indebtedness, as to add value to a work which, notwithstanding my earnest endeavours, cannot but fail to be regarded as imperfect in many of its parts.

HENEY REID.

London, October, 1877.

Contents

CHAPTEE I.

PAGE

CHAPTEE II.