1931-09-19 — Page 2

Use Green Island Cement

for

Constructural Work of

Every Description.

HOW GREEN ISLAND CEMENT IS MADE

Green Island Cement is manufactured from hard limestone and clay, It is necessary that these materials should be finely ground in order that they may come into intimate contact with one another in the burning process.

*

The finely pulverised materials are mixed in a certain definite proportion, roughly one part of clay to three of limestone, and are fed to the Rotary Kiln

In these kilns they meet the hot gases and flames generated by pulverised coal blown in at the other end of the kilns, and after various chemical actions have taken place, they combine to form Portland Cement Clinker.

The Clinker is ground, down with a small percentage of gypsum to regulate the setting time, and Green Island Portland Cement is thus produced.

"Although sounding so simple, in reality the process is an intricate combination of mechanical, physical and chemical operations, needing great skill and care. Nothing but constant and accurate supervision will yield the results so well-known with Green Island Cement; namely, strength, uniformity and reliability.

USE GREEN ISLAND CEMENT

Issued by the

HONG KONG DAILY PRESS, SATURDAY, SEPTEMBER 19, 1931.

ENGINEERING AND

THE APPLICATION OF CONCRETE IN

MODERN ROAD-MAKING.

MEETING THE DEMANDS OF HEAVY AND HIGH

SPEED TRAFFIC.

REDUCING THE TIME OF CONSTRUCTION,

It has been well said that good reason of its inherent rigidity. It noads are essential to modern aivil-occasions little adise, and is invazi-

other material.

BUILDING

be of some uniformity of size. The |usual available sande arc rounded, this being a feature of sea sand, with which however, the presence of

sult is not detrimental.

WELDING AND RIVETING.

COMPARATIVE MERITS.

THE STRENGTH OF TIMBER PILING.

USE FOR FOUNDATION

WORK

It is impossible to any when the of pile foundations for heavy buildings was commenced. Yet, Although

The controversy between the pective schools of thought which favour welding and rivoting respec- tively for structural and other stool. " Further, all kinds of water are work shows no signs of ubatement. not suitable for concreto mixing"

noreto mixing Mr. T. P. Champion has recently ugh the practice is of in

menso antiquity, there are few and suitability can be tested by a thrown more oil on the fire by say subicots about which so little scion- comparison of samples of conorata ing that whilst riveting has beentific knowledge exists, despite its prepared with the water under tert in uso for many years, and in

great importanco, in the engineer- and with those made with puro, thoroughly well-known procesaing world. Many enginears

welding has only been in use for lios thoroughly the high structurat comparatively few years, efficiency and economy of timber

It is true," of

Coured, that the

water.

Granted

Intimate Mixing.

this

right types of com-.

ponents, the quality of the finished conorets will be further determined by the method of mixing. This

process is a critical one, and to

character and strength of the finish

WN

тель

piles, and yet specify piles of

other materials, merely boonum

ed wald, unless subjorted to exhaus

they have no exact knowledge of tive and costly tests, are practical the behaviour of timber work un- ly unknown. The weld itself de der various conditions, Possibly secure the greatest degree of mix Pends on the skill and the con- the failure of a part of Waterloo scientiousness of the welder; with ing, the mechanical method has

Bridge, built on timber fcanda is the conspicuous difficulty of open-almost entirely replaced finnd mix riveting work the human elementtions for some reason or other, ing up concrete roads for repairs to ing, and numerous types of ma mains, this disadvantage is göt över

chines are available for this pur by the exercise of due foresight on the part of the local authorities, .............

Qualities of Components.

pose. These are grouped as batch

and continuous mixers. Many typos of the former are daily seen in operation on road work, these being

to

is reduced to a minimum.

Further, it cannot be denied that

has something to do with this.

If so, all that can bo said is that.

For the continued production of Progarded as accurate in their opera-to building construction, the factor durable. It is a known fact that

reliably sound concrete it is obvious that with three components mixed

#

Bafety, Factors.

its strength does not become in

paired for hundreds of years. In the West Country some of the timber foundations of bridges built in the late thirteenth and fourteenth centuries are as good and sound to-day as when were first put down.

Basential Data.

they

isntion, and modern developments ably plead. If a smoothly finished in road-making mark an epoch in urinon offers hittin grip for stoop highway engineering. The two main incliues, such surfaces can readily features of modern road transport bo treated to overcome this di are the much thoreased loads car culty: Generally there is little cost ried and the speeds attained with of maintenance, and, though there the mechanically-propelled vehicle Those are responsible for much maro wear and tear than was for merly the case with the horne

the safety of a rivat can, her circumstances alter cases, and that, drawa loads of a quarter of a cen-

determined by exacting physical in practically every instance, tim- tury ago, and in putting up ea

chemical tests. Regardless of the

saber pilca, oven when completely officient resistance to this damaging

adaptability of the welding process submerged, are extraordina effect, concrete has played a large part, entering into modern road

of human safety alone precludes the under such conditions wood. de construction, and offering advan

The materials are subjected to uncertain results obtained by this teriorates extremely slowly, and tages aus forthcoming from any by means of a fourth,, viz., water, measurement, and here again ex-process from supplanting the known

there must be some uniformity inactitude goes a long way in secur-and certain results obtained Yet, as far as this country is the choice of these materials, caching the maximum strength of the riveting, concerned, concrete roads are of of which is, therefore, capable of concrete: Volume measurement, was quite recont origin. That they have some sort of standardisation. For for a long time adopted and still is, This is certainly stating the case fully justified the confidenes of the cement, itself very exact speci- but thero appears to be a developing plainly and in a manner that in those responsible for the pioneer-fications have been drawn up and tendency to the adoption of weight vites reply, but it must be remem ing is evidenced by their rapid can be followed by reason of the measurement as being susceptible to bared that closely allied with the adoption and the exactitude with uniformity of the product as manu- more accurate proportioning. The factor of safety is the factor of which, it has come to be recognised,factured by arms of repute. For mixing is effected in rotating drums inspection. During the course of the work, to be of an enduring the other constituents, however, provided with Shfles, and intimate construction not only are rivets Very little appears to have been character, must be carried out. there is less possibility of exact association of the cement with the exposed in the structure, as in and ongineers do not seem to he written regarding timber piling, specification. The general practice,|| surface of the aggregate in all-im- a bridge, for example, they can be agreed as to sizes, depth of driving. The Science of Road-making,

therefore, follows the results. of portant in securing strength. roadily and economically re-examin- and load. There are many abuses as a result of this lack of knowi To-day road-making serves a very tests made over a wide range of Subsequently the laying of eed in order to see if there has been ledge, such as proceeding with the deänite function through which it materials constituting the aggre mixed concrete calls for no less any deterioration... we on work without suitable data on exorcises some influence on everygates and the water used for mix skill, in that a number of conditions The protagonists of welding for which to base the necessity for piles._determination of the length industry of moment in this country, Ing.

are essential to the production of steel structural work have a sound required, use of improper equip- and the application of concrete to As regards aggregate, this in the the perfectly road. As little trane answer, apparently, to the argument, under-driving, or what is this end, is by as means a negligible usual conducte constitutes some 75 portation should be undertaken as ments of the riveting school. They perhaps worse, over-driving of factor in modern industrial develop. to 85 per cent. of the whole mass, feasible, the mixture being laid as can point to the fact that, given perhaps, one of the greatest living pile Mr. J. F. Seiler, who is, and the characteristics of this large soon as possible after leaving the proper equipment and skilled work authorities on structural timber For very many youre we find to proportion must, therefore, be of machine, and no material being men, there is no reason why a weld-work, tells us thas one of the most serious of these abuses is the an be content with the type of road considerable importance. The used which has, through uncontrolled joint should be any less strong which derived its name from its material may range from very fine able circumstances, been allowed is, than any other part of the struc- originator, Macadam, who, in con-particles to lumps of two to three stand for any length of time after ture... junction with Telford, iaid an elabo- inches, and the rough, classification mixing. These are, matters yell At present, however, the majority rate system of roads in the High-into fine and coarse aggregate is within the experience of the higa of contractors consider, that riveted laude, and laid also the foundation mainly based on a dimension of way engineer, while the subsequent construction in by far the majority of a scientific recognition for the inch, In the case of the coarse treatment of the surface by the vari of cases affords results and costs art of road-making by taking elabo-nggregate material the compressive ous methods of curing goes a long that cannot be approximated penetrations undergone by a pilo rate precautions that the founda strength is of considerable importway towards developing the requir-welding, tions should be well and truly laid ance, as this should obviously noted strength of the concrete...

menta,

"

....

ין

igning of arbitrary load capacit tive of conditions of scil, manner of driving or position of piles, or their arrangement in groups.

Pile capacities have been deter, mined for many years. past by formulne based on dynamic far- tors of the energy delivered by a hammer Blow in counection with

due to such blows.

..

GREEN ISLAND CEMENT CO., LTD. ||ot only in the method of construc- course aggregate over a wide range, these joints the method of laying ing that of the usually, accepted in groups, Mr. Seiler points out

2ND FLOOR,

EXCHANGE BUILDING.

In certain cases these formula have been found to give conserva- to meet the more exacting condi-be less than the finished concrete. Further, the contraction whichi

tire results for individual · piles. tions which were to be imposed Otherwise the strength and resist occurs in setting necessitates soms not otherwise, attainable with ordi- but more often it has been found upon them with the advent of in-anve to wear of the concrete is not filling in between the successive slabs month. These concretce, moreover, sulta completely at variance with nary cement concrete under a that actun) loading tests give ro- dustrial activity. Science thus early came to be applied to road-making, largely influenced by the type of which are laid down. To minimise develop a degree of strength exceed these formulae, especially for piles tion, but later in choice and treat- Sofeter aggregates of the limestone alternate slahn can be adopted, and of consolidation by the application sign loads of 20 tons for timber mixture. They are further capable that the practice of assigning de ment of the materials available for variety are increasingly possiblo the production of hard-wearing sur and used with the wider adoption by filling in the intermediate spaces of rolling within the period of set-piles and of 30 to 35 tons for con- faces. In these latter days of rond of rubber tyres for the heavier afterwards the width of joints isting, a practice not possible with crate piles is ona which cannot be construction, science has been very types of vehicles in place of steel reduced. These joints are subse their rapid initial setting.

ordinary cement concretes owing to justified on the basis of compara much concerned with the problems tyres, which effected considerablo attaching to the behaviour of a wear and tear on the earlier con quently filled in with a waterproof

Retiforcement, number of materials used in road | crets and other types of roads, ' construction, and this is notably For the aner aggregate, sand

elastic material.

Thus following the procedure

tive loading testa, because no such tests covering any proper scope of the subject exist, an

The contention that heavy

the case in the processes of the necessitates some careful selection, which has for so long been the us in concrete road constructions concrete pile penetrates less than 3

setting of cement.

application of concrete. There is Many advantages attach to the the durableness of its surface and its freedom from corrugation by

load capacity is one that cannot timber, pile under a given amount affords a correspondingly greater of energy delivered. and therefore

he maintained. Obviously. it does

not take into account the fact that

$

The application of reinforcement It should be free from clayed. cement to the Kand; and, while is required before the road can be which reduces wear and offers. bet material which prevents sticking of tom, a period of some three weeks now extensive. There is first the ndvantage of the added resilience, angular particles are not necessary, it is desirable that the grains should reopened for traffic, to which must tor qualities than a slab of a rigid be added the time taken in the type. In addition, there is a more preparation of the road to receive even distribution of the load on the the heavier piles must absorb. the concrete. These long delays ground below, this making it pos large proportion of the kinetiolen constitute one of the chief dissible to apply concrete to relatively argy of the hammer blow before advantages of concrete road con- softer grounds. Moreover, the nost struction, but the difficulty is not of the reinforcement is probably useful work of netual pene, insuperable; it being usual to deal counterbalanced by the reduced ration can be effected, with one half of the road surface amount thickness of the concrete ut a time.

applied, together with reduced ex- ravation, costs, did a

In course of time there is likely justifiably be based, according to to-occur""some" "subsidence of the Four authority: on éross-sectional The desirability of decreasing the earth upon which the concrete has strength

areas of the suri time for the maturing of the con-been laid. With reinforcement the face but not necessarily on crote so that the road may be open-concrete more readily, adapts itself dynamic factors involved in ed at the earliest possible moment to this change, while further the driving of various typer. has naturally received considerable changes caused by expansion and of piles. In this connection it i attention. Some variation in the contraction are, more evenly dis to be noted that timber in com- procedire ensures a reduction of tributed throughout the

Be wise and see that, your new building

STEEL FRAMED

Why?

Because a STEEL FRAME gives you— More floor space and therefore More rental válue,“ ·

More window space,

Greater facility for alterations and additions, Maximum strength and dependability, Maximum salvage value.

The illustration akows the A.P.C. Building, Hong Kong, designed by Messrs. Palmer, & Turner, for which Dorman Long Applied the steelwork.

Dorman Long & Co., Ltd., Middlesbrough & London.

Rapid Hardening Cements.

3.

Timber and Concrete. Comparisons of c capacity may

strong as concrete.

this delay, and the influencing fasa reduction of cracking, with pression is more than twice tors include a decrease in the The method is consequently ex- But even these consideration do amount of mixing water with also atensively applied, and definits not afford anything but the most richor cement mixture. More time specifications are forthcoming re- general approach to the problem, is also taken in the mixing process,garding the qualities of the rein- because soil conditions may not and, after laying, the concrete is forcoment. In practice several wall- 1 doveloy the crossectional strength kept damp. A further means of known types of reinforcement have of a pile, in skin friction on its time saving is that of the addition acquired a large vogue, the special: surface.

of an accelerator, such, for exam requirement of such reinforcement. It appears that cross-sectional ple, as calcium chloride, on which having received the closest atten- strength does measure the ultimate some notes appear in the regular specification of an within the usuni case this is greatly in another article tion and been adequatly met. Thus load which a pile can sustain, but on this page.

ro

A much reduced time for the oromate tensile strength of 60,000lb. || in excess of values which practic duction of the strength of concrete per sq. in and a bending quality all judgment i would" permit.” The is, however, achieved by the adop equivalent to bending through: 190 development of frictional tion of a variation in the componi- deg, round one diameter, subsesistance in a given soil is subject tion of the cement. The behaviour quantly straightening out without to many factors about which little of aluminous cements was observed cracking in the cold, is being more or nothing is known, and it de na far back as 1009; but as a prae- than met in the several types of pendo also upon spacing betw tical proposition the power matori reinforcement which are being ex- the nite when in groups, like nfs received considerable intensive | tensively applied,"

It certainly soon, as a result research, with the result...... that This combination of steel and of lengthy research work, that pile cements are availabis

which w

while concrete has done much towards behaviour is principally a matter. they may be relatively slow in ect meeting the insistent demands for of the characteristics of the not ting, very rapidly hardon and at-improved roads to withstand the into which the piles are drive. tain in a day a. degree of strength stresses of modern mechanical trans" and "Argely independent of

(Vontinued on neer Column.).⠀4hport

pile