A practical and scientific treatise on calcareous mortars and cements, artificial and natural : containing directions for ascertaining the qualities of the different ingredients, for preparing them for use, and for combining them together in the most advantageous manner, with a theoretical investigation of their properties and modes of action ; the whole founded upon an extensive series of original experiments, with examples of their practical application on the large scale

Front matter

PRACTICAL AND SCIENTIFIC TREATISE

ON CALCAREOUS

MORTARS AND CEMENTS,

Author's Preface

The art of composing calcareous cements was confined, till within the last few years, to the knowledge of a small number of facts, and to the observance of certain rules long since admitted into use without examination, on the authority of Vitruvius and the architects who followed him. But the rules were almost always found to be at fault, and the facts, for want of correlativeness, were of but little aid. Could we, for instance, manufacture good mortar in France, by mixing three parts in bulk of dry pit sand, or two of river sand, with one part of slaked lime derived from a white marble of great hardness ? Such, however, are the proportions of admixture, and the characteristics of good limestone pointed out by Vitruvius. It was of little importance besides to those, to whom it was impossible to procure it, that the pouzzolana of Italy and the Dutch tarras were possessed of extraordinary binding qualities; that lime eminently adapted for hydraulic works was to be found at Metz, Viviers, Nismes, &c, in France, at Lcea in Upland, at Aberthaw in England, and elsewhere. With all this information, and even adding to it the discoveries of the Swedish Baggc, and Count Chaptal, regarding the transformation of some schists, and certain ochreous clays into pouzzolanas by calcination, it was not the less necessary to work by guess in most instances, or to trust to obscm-e analogies for the success of the most important works. One engineer vaunted the efficacy of the powder of tcell-burnt tile, another looked upon smithy slag and iron-dross as the finest ingredients. These again, on the other hand, asserted, that such substances are destitute of energy. Lastly, this difference of opinion extended even to the manipulation of the compounds. Was the lime to be slaked with much water, or to be allowed to fall to

IMU I powder after having immersed it for a few second? ? .Should it be applied hot or cold ? &c. Even- plan had its partisans ; and what doubtless appears paradoxical was, that each method too was supported by experiments and testimony, of which it was hardly possible to dispute the authenticity.

We shall leave it to the reader to appreciate a state of things like this, and to decide whether such a chaos of opinions and opposing facts could or could not make up a science. — a doctrine of calcareous cements. Perhaps it may be replied, that at the epoch of which we speak, builders had learnt to erect bridges, locks, Mc. without either tarras or pouzzolana, and in countries where the lime possessed no extraordinary quality. Without denying this truth, we must remark, that most of these works have not endured, nor can continue to endure, but by frequent and expensive repairs. That on many canals it has been necessary to reconstruct a great many locks, whose side walls were in a few years found to be quite stripped of mortar. That a multitude of dikes, sluices, weirs, («* barrage?,*') and aqueduct-, of recent construed' >n, already exhibit all the characteristics of age. without the possibilitv of attributing these unexpected dilapidations to any other cause than the bad quality of the mortars or cements made use of.

These facts, known to a number of engineers, have long since attested the insufficiency of the art : and this insufficiency exhibited itself more and more, owing to the multiplicity of marine works called for bv a constantly increasing commerce. It wa- to put an end to such a state of things, that we, in 181 '2, commenced our experimental researches, published in 1818. The subject, so to speak, is one of intrinsic importance, and consequently to discuss it merelv is sufficient to attract public attention. We may. therefore, be allowed to say. laying aside personal vanity, that the experimental researches on lime and mortars have been the subject of serious examination by chemists, architects, and engineers. Certain theoretical points, independent of general results, have given rise to the-e di -. which have themselves stimu-

PREFACE. Ill

lated us on our part to new labours. Experiments in contrast with one another, undertaken in various parts of the kingdom by order of Mr. Becquey, Director-General of Public Roads and Mines, while they consolidated the necessary fundamental points established by us, enlarged the domain of facts to such an extent, that it became necessary to re-digest the whole, in order to arrange and compare them together. But by this very operation, owing to the multiplication and mutual support of the truths, they have added fresh confirmation to those which we were already possessed of. They have also enabled us to contract the scale comprehending them, both by leaving us at liberty to adopt a mode of classification before impossible, as well as by affording us the power of casting into notes a crowd of details and historic or scientific documents, useful to consult, but not indispensable to the understanding of the whole.

It is, moreover, in the nature of things to become more simple, in proportion as they approach perfection ; and this is the more fortunate, as now-a-days, much more than formerly, large volumes create alarm, and are no longer read.

These explanations having been given, we are anxious here to make known the fresh obligations which we labour under to the analytic and synthetic labours of Messrs. John and Berthier, on calcareous compounds and hydraulic limes ; to the researches of M. Bruyere, Inspector-General of Roads and Bridges, on the manufacture of artificial pouzzolanas and cements, resulting from the calcination of clays combined with a small proportion of lime ; to the very remarkable experiments of Messrs. Avril and Girard de Caudemberg, Engineers, the first on the psammites of Finisterre — the second on the arenes of Perigord ; to the examination of the limes of Russia by Col. Raucourt, an examination which has led that Engineer to enrich the science with numerous important observations ; and lastly, to the interesting results obtained by M. Lacordaire, Engineer, in using the hydraulic limestones imperfectly burned, as natural cements.

1\ I'HLIACL.

There are services of another kind which require no . acknowledgment — such is the generous and enlightened maimer in which M. Bruycre, Inspector-General, first, in [Q18, obtained for rny work the attention and support of the Director-General and Council of Roads and Bridges ; such alpo if the succour afforded to this work by the honourable mention of it which Messrs. Gay-Lussac and Thenard have been pleased to make in their Lectures in the u Ecole Polytechnique ;" in the Syllabus of his Lectures on Building by ,M. Sgauzin. Inspector-General ; and lastly, in an able Report to the Academy of Science?, by M. Girard, Member of the Academy.

TRANSLATOR'S PREFACE.

The merits of M. Vicat's valuable researches into the composition of mortars and cements are already too well known, to render it necessary for me to apologise for an endeavour to extend their usefulness, by submitting them to the public in a more accessible form. But as the motives which induced me to undertake this work, and have encouraged me to persevere in its fulfilment, may require explanation, I ought not to refrain from making them known, nor from claiming that indulgence for the result of my labours, which the peculiar circumstances under which they have been accomplished render necessary.

Having been occupied for many years in the construction and repairs of numerous public buildings, the charge of which devolved upon me in the performance of staff duties, I was long embarrassed, in the endeavour to give durability to works executed under my superintendence, by many difficulties arising from the defective quality of the cements employed, the dampness of the situation, and other causes at the time unknown.

Anxious to remedy these evils, I engaged in a series of experiments, in which numerous modifications of the processes previously employed, and even.- suggestion which could be gleaned from the scattered hints contained in the writings of the various English authors who have incidentally touched on the subject, were put to trial, both with reference to the durability of the compounds, as well as their economy on the large scale. But although these endeavours were followed by many promising results, it was not until I became pos-

VI TRANSLATOR B PREFACE.

sessed of M. Vicat's Work, that the theory of the composition of mortars and cements was developed in a sufficiently satisfactory and comprehensive manner, to enable me to take a full view of the varied resources found within the limits of almost every locality, for the fulfilment of the objects of which I was in search. But, systematic and plain as M. Vicat's instructions and experiments are when well understood ; yet it was not without much labour, in repeating many of the experiments, and the perusal of other French authors on the same subject, that I was enabled to overcome the difficulties occasioned by my imperfect acquaintance with the exact meaning of the numerous technical termemployed in it, and fully to appreciate the originality and appropriateness of the experiments, and the depth and philosophical accuracy of the reasoning founded on them. Having surmounted these obstacles, and felt the great value of the copious information placed at my disposal, I could not look back upon the pains which it had cost me to effect my object without being led to consider, that others similarly situated with myself might have the same impediments to contend with; and that I might assist future incpairers. by placing the labours of M. Vicat within the reach of those, who might not possess sufficient leisure to give that attention to his work which I had found to be indispensable.

Of the desirableness of such a work, indeed, it needed but little consideration to Batisfj me; for though intimately connected as such researches are with the success and durability of our most important const ructions, and with the security and domestic comforts of every class of civilized society: it is remarkable, that since the publication of Dr. Iliggins, nowrendered obsolete by the rapid strides which the art has taken since his time, no English work on this subject has yet appeared. Nor have the investigations connected with it, hitherto, attracted the attention of any of the distinguished philosophers, to whom science and the arts are in other respect* so largely indebted.

TRANSLATOR S PREFACE. VU

At a time, therefore, when the rapidly extending demands of a quickly progressive civilization, daily give birth to new and stupendous undertakings, there could be no doubt as to the benefits which must result from bringing before the public, the labours of those who have devoted themselves to the study of this very important and hitherto neglected branch of Architecture, and of placing within their reach the manv valuable facts brought to light bv them.

But of my own fitness for this undertaking, even with the advantages of expected leisure under which it was commenced, I could not avoid feeling the greatest diffidence ; nor should I have ever ventured to incur so great a responsibility, had I not been encouraged by the consideration, that much which could not fail to be of service, might be effected by the mere exertion of persevering industry. And that, although, as I felt conscious, numbers might have been found infinitely better qualified than myself to do justice to the task; yet, that the very circumstance of superior fitness, joined to the increasing demands upon the talented members of the profession to whose province it would most properly belong, would be sufficient to prevent the public from ever deriving the benefit of their assistance.

Under the influence of these considerations, therefore, and in the hope of thereby finding useful and instructive occupation, for the leisure which an absence from my duties on account of ill health would afford me, I made up my mind to commence the task. But I had not proceeded far, when I was unfortunately deprived of the advantage upon which I had principally relied for success, by being called upon to apply the time I had intended to devote to this object, to the service of Government in a different pursuit ; whereby I was deprived of the ability to devote that attention and study to it, which it was my earnest wish to have done.

These causes must, I fear, necessarily be pleaded as an excuse, for those inaccuracies which I cannot hope to have escaped viii TRANSLATOR S PREFACE.

from : and which will, I trust, be treated with indulgence. In the general design and execution of the work, however, I have not failed to keep in view the convenience of the reader, in so far as it lay in my power to add to it, or to the general usefulness of the volume. I have therefore, throughout, endeavoured to communicate whatever information it was in my power to collect, either from the published works of others, or from my own experiments, in illustration or support of the opinions or statements contained in the text. The whole of the measures made use of have, also, except when clearly unnecessary, been reduced to the corresponding English standard ; a process which has also been applied to the very valuable results collected together in the Tables. Thus, these experiments now admit of a ready comparison with similar ones made in this country, and the reader will find no difficulty in forming a clear apprehension as to the efficiency of the processes to which they are applied as tests. It may be proper to add, that these calculations have been made from tables of the correspondence of English and French weights and measures, given at the end of Ure's Chemical Dictionary (Edition of 1824).

In the first, or more practical part of the volume, explanations have been given in the notes, of such scientific terms as may not be familiar to the general reader. This, however, has not been done in respect to all the notes in the Appendix; as many of them, consisting of purely scientific reasoning, conk) not, in the limited space of a note, have been rendered perfectly intelligible to those by whom the terms themselves were not understood.

These additions, with that of a copious Index, and a more di-tinct separation of the various subjects severally treated, will, I hope, materially assist the perusal ; more particularly by obviating the confusion liable to be occasioned by the apparent contradiction of the different directions given in the work, applicable to various circumstances. In the latter part of the volume, I have ventured to take a liberty with respect to its

TRANSLATOR S PREFACE. IX

arrangement, to which I was prompted by a desire to attract the attention of the scientific reader to a subject hitherto little noticed. I have for this purpose converted the " note on the theory of calcareous mortars and cements" into a distinct chapter (the seventeenth); to which the appendix to that note, together with the particulars of some experiments by myself in prosecution of the same subject, have formed an appropriate appendix. To this more prominent position in the body of the work, the theoretical investigations above mentioned seemed to me to be entitled, both from their close connexion with and essential influence over successful practice, as well as from their intrinsic value and philosophical interest. Its discussion is accompanied, moreover, by so many hints calculated to awaken attention and stimulate inquiry, whilst so little seems to be wanting to complete the evidence, that we may soon hope to be possessed of a sufficient number of facts, to form the basis of a correct theory of the hitherto illunderstood causes of solidification, under all the various circumstances in which it takes place.

In regard to the use of some new terms which I have found it necessary to apply, it may be right to explain, that after trying many substitutes taken from the technical language of the best authorities on this subject, I found M. Vicat's classification so different and so much more methodical than any which has hitherto obtained in this country, that I should have run the risk of sacrificing the clearness of his arrangement, had I attempted to introduce any synonymes taken from the English language to express his meaning, in lieu of the simple translation to which I have confined myself. Other words, used for the purpose of defining substances hitherto classed by us under a more general category, and consequently intended to mark distinctions at present unknown, such as " arenes," " psammites," &c, I have thought it advisable to convert at once into English terms, taking care to explain their meaning on their first application.

X TRANSLATORS PREFACE.

Of the particular merits of the numerous practical instructions and varied processes contained in this volume, it would perhaps be premature in me here to speak ; the most satisfactory recommendation being the experience of those, who may have occasion to put them to the test of actual trial. I ought not, however, to omit to notice a circumstance which it would be injustice to M. Vicat not to refer to. This is, that although the processes he has laid down for the manufacture of artificial hydraulic compounds are of a comprehensive nature, capable of accommodating their results to the exact wants of the architect in every situation, thus including all the various kinds of Roman Cements, &c. ; yet, it will be observed, that his own practice seems to have been chiefly confined to the adoption of the hydraulic limes, in lieu of the more energetic cements more generally used in this Country. This preference may expose him to the opposition of many firmly-established usages and opinions, where the latter practice has so long and successfully prevailed, with respect to the justice of which it would not become me to hazard an opinion. M. Vicat has, however, relieved me from that necessity, by expressing his own very decidedly, in his declaration (in Chapter XV., Art. 263)] that the superior adhesion of the hydraulic limes over our (so called) Roman cements, must inevitably, in time, give them the preference, whenever the comparative merits of the two are fairly known and appreciated. Now, without entering upon the discussion of this question, I may remark, that it appears to be one in which a contrariety of opinion may be occasioned by a difference of situation and circumstances. Thus it may perhaps be important, in considering the merits of the two systems, to recollect, that in one the means of minute mechanical division are an essential element, in the other, that it. is unnecessary ; and that this element which in one situation may be obtained at a cheap rate, may in another be expensive or unattainable. The hydraulic limes, therefore, which do not require to be ground previous to use, are at all events, whatever may be their other merits, more especially suitable to

TRANSLATOR S PREFACE. XI

those situations where the facilities of mechanical agency cannot be resorted to. This circumstance would in itself be sufficient to justify M. Vicat's opinion; but I have now referred to it principally to point out, that the use of ground cements, valuable as they are in our constructions, are better adapted to the vicinity of a large capital, where it is of little importance that the builder becomes dependent upon others for his supply, than for a remote situation or a new country, in which the unground limes cannot fail to be preferred, from the facility with which they may be prepared by the mason himself. The difference, in fact, consists in this, that the ground cements, of whatever kind, will ever be furnished by manufacturers, whereas the hydraulic limes may at all times be prepared by the common workman, without machinery, and at a cost not much exceeding that of common lime (vide note to App. XVIII). And it will be in reference to this advantage, in addition to those pointed out by M. Vicat, and in opposition to the inconveniences which may be occasioned by the defect peculiar to them, their comparatively tardy solidification, that the engineer will be guided in making the selection best suited to his situation and exigencies.

Moreover, it is not merely in the accuracy of the details of his valuable invention, that M. Vicat has done the most service to the profession by the publication of his work ; we must not forget the variety of other processes which he has illustrated and verified by numerous and exact experiments, and by which he has increased the resources of the practical engineer in every situation. And it is by the broad light thrown upon the relations of the numerous but ill-known ingredients, that he has placed within his reach a clew for the formation of compounds, hitherto guided by empirical rules, seldom derived from and therefore not adapted to the circumstances under which they are to be applied.

It now only remains for me to express my acknowledgments for the assistance of which I have availed myself, in the execution of my small part of this volume. Of the pubxii translator's preface.

lished works to which I have had occasion to refer, I have made a point of duly stating the authority to whom I have been indebted; and to the distinguished authors to whom these obligations are due, I have merely to add the names of my friend Dr. Malcolmson, whose valuable services will be recognised in various parts of the Work, and of Colonel Sim. of the Madras Engineers, whose kindness in the ready communication of the results of his extensive experience in the processes for the manufacture of the celebrated mortars and stuccoes of Madras, has added another favour to the many debts of gratitude long due to him.

Section I

VARIOUS LIMES, OR AGENTS OF ADHESION IM CALCAREOUS MORTARS AND CEMENTS.

CHAPTER I. Pages

Of limestones, and the various limes they furnish. — Distinction of the known limes into rich, poor, and hydraulic limes. Characteristics of the different limes. — Method of distinguishing and classifying them. — Relation between the qualities of limes and the chemical composition of the stones whence they are derived 1

Chapter II

Calcination of limestone on the large scale. — Conditions necessary to render the calcination as easy as possible. — Case of the rich limes. — Case of the hydraulic limes. — Different kilns made use of. — Average quantity of combustibles required for the calcination of a cubic metre of lime. — Irregular action of the coal kiln by slow heat 13

Chapter III

Of artificial hydraulic limes. — Two modes of preparing them. Comparison between the hydraulic limes and the water-cements used in England. — Description of the processes followed by M. Saint Leger at Paris. — Average price of

the artificial hydraulic limes 20

b li i Ai'.i i OB < "\i 1 S i •

CHAPTER IV. Page?

Of the slaking of lime. — Ordinary process. — How abused. Expansion of the different kinds of lime. — Effect of cold water upon rich lime in effervescence. — What renders lime sluggish in slaking. — Second process of extinction. — How it ought to be practised in order to reduce rich lime well. Water absorbed. — Expansion of the various limes, in powder not compressed. — Third process. — Water absorbed. — Expansion.— Order of the throe processes in reference to the degree of division communicated to the lime. — Action of the carbonic acid of the atmosphere upon lines differently slaked. — Method of preserving the different limes before and after extinction 26

Chapter V

Of the hydrates of lime, or solids resulting from the simple combination of water and lime. — Influence of the degree of consistency given to the hydrate in the first instance. — Action of the air. — Mode of exhibiting this action. — Action of the water. — Use that may be made of the hydrates in the arts. 34-

Section II

VARIOUS INGREDIENTS WHICH UNITE WITH LIME IN THE PREPARATION OF CALCAREOUS MORTARS AND CEMENTS.

Chapter VI

Of sands. — Of arenes. — Of psammites. — Of clays. — Of volcauic or pseudo-volcanic pouzzolanas. — Of the artificial products analogous to pouzzolanas. — History of these substances ... 43

Chapter VII

Qualities of the ingredients mentioned in the preceding chapter. — Definitions — inert substances — slightly energetic

TABLE OF CONTENTS. Ill

Page?, substances — very energetic ditto. — Insufficiency of their physical characters to denote the qualities specified under the above denominations. — Approximate chemical methods of recognising them ; by means of acids, by lime-water ... 52

Chapter VIII

"Manufacture of artificial pouzzolanas. — What are the substances most proper for such fabrication. — Conditions to be fulfilled to attain the object. — Influence of a slight calcination and the contact of the air. — Nature and quantity of the ingredients in a good pouzzolana which are acted upon by muriatic acid 58

Chapter IX

Mutual suitableness of the ingredients, with the various limes, in relation to the destination of the mortars or cements for the preparation of which we use them. — Case of constant immersion. — Case of alternations of dryness and moisture. Case of exposure to the weather 64

Chapter X

Mortars or cements intended for immersiou. — Choice of proportions.— They are variable. — Limits established for certain cases. — The proportions exert a more important influence the less energetic the mixed substances are. — They must be modified according to the use for which the mixtures are intended. — Choice of the process of slaking — Order of pre-

b 2 iv TABLE OK CONTENTS.

Pages, eminence of the three known processes, in reference to the nature of the lime made use of. — Manipulation or manufacture— How it ought to be conducted under various circumstances.— Application to use, or immersion. — Difficulties to be overcome, huw to manage them. — Old method defective. Action of the water upon the parts of immersed mortars or cements with which it is in immediate contact. — Influence of time 67

Chapter XI

Mortars or cements constantly exposed to the weather. — Mode of correcting the bad qualities of rich limes. — Use of sand in different mortars — Opinion of the ancients upon the quality of sands. — Influence of their size — it varies with different limes. — Method of mixing them. — Choice of proportions,— with rich limes, — with hydraulic limes. — Choice of the process of slaking ; — it is the same as in the case of immersion. — Fabrication. — Conditions of a good manipulation.— Use — difficulties to be overcome. — How to attain the object. — Precautions in respect to drying to be taken after application. — Very remarkable influence of time upon morta» of rich limey after many centuries 84

CHAPTEfl XII.

Mortars or cements subjected to the constant influence of ■ damp soil — Influence of the coarseness of the sand. — Of the process of slaking. — Proportions. — Application to use. — Of concrete 9g

( IIAPTKR XIII.

Of the vicissitudes to which cements and mortars may be exposed. — Influence of these vicissitudes. — Case of frosts. — Effects of the proportions and the size of well-mixed Nmdi ]qo

TABLE OF CONTENTS. V

CHAPTER XIV.

Pages.

Influence of beating upon the resistance of mortars — Cases in which it is more injurious than useful. — Difficulties which mortar when used as a plastic substance opposes to moulding.— Case in which these difficulties disappear 106

CHAPTER XV.

Natural cements. — Composition of the calcareous minerals which produce them. — Their advantages, their inconveniences.— All argillaceous limestones when imperfectly burnt afford natural cements Ill

CHAPTER XVI.

Of ancient mortals compared with mortars of the middle ages. Description of the cement used in the Egyptian Pyramids. State of the art in Egypt; — amongst the Greeks; — amongst the Romans. — False opinion of the moderns as to the cause of the hardness of ancient mortal's. — Known limits of absolute resistance of mortars 1 14-

CHAPTER XVII.

Theories of calcareous mortars and cements ; their insufficiency. M. John's experiments. — Macquer's hypothesis. Loriot and Lafaye's opinions. — Definitions. — Four cases presented by aggregates. — Probable consequences of the first case ; ditto of second case; — ditto of third case; — ditto of fourth case. — Theory of the solidification of hydraulic limes. — M. Petot's experiments. — Remarkable influence of sand on the absorption of carbonic acid in old mortars. M. Berthier's opinion. — Its insufficiency. — Concluding remarks 124

\1 1ABI.E OF I

Appendix

NOTES OX CHAPTER L

No. Pages.

1. History of lime and calcareous minerals 141

2. Chemical methods of appreciating the qualities of lime-

stone*— Fruitless attempts of the ancients in this respect... 1-13

3. Of the way in which we have been enabled to add to the

facts made known in 1818. — Authenticity of the i

results 145

4. On the colour of limes ib.

5. Method of analyzing a magnesian limestone by hydration 146

6. Account of the Madras magnesia 14-7

7. History of artificial hydraulic limes 150

NOTES ON CHAPTER 11.

8. Effects of calcination on compound limestones. — Mutual

re-action of the constituents 152

9. Influence of aqueous vapour upon the calcination of lime-

stones.— Experiment by M. Gay-Lussac ib.

10. Fact relative to calcination in a clos< i --> I 153

11. Consequence of the imperfect burning of limesl

Contradictory experiments on this subject Ml

cperiments upon the different quantities of combustibles used in tin burning of Kme 157

13. Sensible improvement which takes place in the burning of lime with coal, by very alight modifications in the management of the fire, and in the selection of the combustible ... 158

11. Irregular action of the coal kilns by slow heal (Jkm ctmtmu). — Use of turf 159