As in the case of roadways, so with footpaths: the foundation is of primary importance, whatever material may be used for the surface. Where this material may be classed under the head of “Paving,” concrete[101] makes the best foundation. For gravel, tar paving, or other similar surface, a hard core bottom well drained is sufficient. The materials of which a footpath can be formed are almost innumerable, but the following may be given as embodying most of them:

(1.) Natural asphalte, compressed and mastic.

(2.) Yorkshire flagging—Caithness flagging.

(3.) Blue lias, and Devonian limestone flagging.

(4.) Concrete.

(5.) Bricks.

(6.) Granite slabs.

(7.) Artificial asphaltes, including tar pavement.

(8.) Gravel.

First on the list stands natural asphalte, compressed and mastic.

The compressed has been thoroughly described in the preceding chapter; it is sometimes used for footpaths where there is a very heavy traffic, and answers admirably.

I will, however, now deal solely with mastic asphalte, which means the rock ground to powder, mixed with a certain proportion of bitumen to act as a flux, and then subjected to heat; this is sometimes used in conjunction with fine sharp clean river sand, but more often with finely crushed stone about the size of peppercorns, and is styled “gritted asphalte.”

As long ago as the year 1838, Mr. F. W. Simms speaks of asphalte mastic from Pyrimont, near Seyssel, and says “it may be considered a species of mineral leather”[102]—a very good description of its surprisingly tough, hard, durable and pliant properties.

The usual method of the preparation of the mastic is as follows:—

According to the amount of bitumen contained in the natural stone, from 5 to 8 per cent. of refined Trinidad bitumen[103] is placed in a large caldron which is usually provided with agitators driven by steam power; when this is thoroughly melted, the powdered asphalte is added little by little, the heat being raised to between 390° and 480° F., the mixture kept well stirred and “cooked” for about five hours. It is then turned out into iron moulds, most companies having a special pattern with a trade mark for this purpose.

The caldrons generally used contain from 1¹/2 to 2 tons of mastic.

Some companies in large towns are provided with caldrons on wheels, commonly called “Locomobiles,” in which case the grit is mixed with the mastic in the fixed caldrons, and the whole mass run out into the locomobiles (which are also provided with agitators worked by an endless chain attached to the axle of the wheels), and transported direct to where the work has to be done. This system, though undoubtedly the best, is not practicable except in large towns; the more usual method of laying mastic footpaths is to send the asphalte cakes to the works, where they are remelted in small round street caldrons, containing from 8 to 12 cakes each, weighing from 40 to 50 lbs., the grit being sometimes added in the fixed caldrons, sometimes in the street caldrons, this amount of grit varying from 20 to 60 per cent. according to the nature of the work.

The grit makes the asphalte more difficult to spread, but it lessens the cost and makes a very durable path. The affinity between the asphalte and grit is so great that, in breaking a sample, the actual pieces of grit will be found broken in half.

The asphalte should be spread from ¹/2 to 7/8 of an inch in thickness (if compressed 1 inch is the minimum), and should be brought hot on to the works in covered caldrons on wheels, the test of its being ready and fit to lay being made by plunging a wooden spatula into it, which should come out without any of the asphalte adhering to it, and also by jets of light smoke darting out of the mixture.

The mastic should be taken from the caldron with a warmed ladle, and put into buckets previously heated, then thrown out on the concrete (which should be perfectly dry) near the spreader, who spreads it skilfully with a wooden stave, spreader, or spatula. The surface should then be floated and dusted over with fine sand, portland cement, or stone dust.

Dishonest contractors sometimes substitute inferior materials for natural asphalte, such imitations being made of ground chalk, fire-clay, and pitch or gas tar, or ground limestone mixed with bitumen.

A sample of the footpath after it is laid should be cut out (this is easily effected by heating the surface with a piece of hot mastic), in order to see that the proper thickness is given, and by applying a light to the sample, the smell will readily tell if real asphalte or any inferior material has been used. Stockholm tar or common pitch should not be allowed to be substituted for Trinidad bitumen, or it will spoil the mastic.

Asphalte mastic footpaths are excellent in every way, the only objections to them being the necessity for the grit, and the temporary unpleasant smoke and smell whilst being laid. It is also necessary to put stone sills round the cellar openings and coal shutes, etc., for it to butt against, but it makes an invaluable pavement, especially for courts, alleys, back yards, etc., for sanitary and other reasons.

The proportions of asphalte, bitumen and grit are given as follows by Mr. Delano in his translation of a paper by M. Ernest Chabrier, on the applications of asphalte.[104]

“One ton of sanded mastic requires 13 cwt. of pure block mastic, 2 qrs. 12 lb. of bitumen, 7 cwt. of grit or sand washed and dried,” and it takes 2 cwt. of coal to heat it. He further says that one workman can easily prepare 3 tons of material in 12 hours.

The following table gives the number of square yards that a ton of prepared Sicilian rock asphalte will spread.

	Without grit.		With about 25 per cent. of grit.	Thickness.
	square yards.		square yards.	inches.
	63		80		³/8
	51		65		¹/2
	32		40		³/4
	26		33	1
	16		20	1	¹/2
	12	¹/2	16	2

A skilled workman properly assisted can lay 140 to 180 square yards in a day.[105]

With regard to the price of asphalte mastic footpaths, this is quite a local question, and is not worth while discussing. The life of a footpath thus treated may be reckoned at about 15 years under ordinary traffic; the concrete will remain untouched and what is left of the asphalte may be remelted, so that a renewal is not so costly as the first expense.

Yorkshire Flagging.

—This pavement is too well known to need any description from me; it is an excellent pavement in many ways, and is most pleasant to walk upon, there being a cling or foothold not experienced in any other material.

The objections to this description of pavement are:—

(1.) Its first cost, which is undoubtedly high as compared to its durability.

(2.) The fact of uneven wearing: one stone will be found soft next to a hard one; the former wears, leaving a pit which forms a pool for water in due course, and has to be removed.

(3.) Unless very carefully bedded, a stone will see-saw; this is very unpleasant in wet weather, water accumulates beneath, and as the pedestrian treads on one end of the stone a squirt of dirty water up to his knees, and a stumble, remind him that the stone is loose.

(4.) Liability to crack when any heavy goods are thrown upon it.

The following specimen specification for Yorkshire flagging pavement may be of use.

Specimen Specification for Yorkshire Flagging Foot Pavements.

The old flagging (where and when directed) to be taken up, refaced, squared, and relaid.

The new flagging is to be chisel-dressed to a fair face, true, out of winding, and not less than 3 inches thick,[106] to be properly squared and not pitched off only, or undercut, but to hold good to the square; to have not more than fourteen pieces to the hundred superficial feet; the joints must be set flush, and bedded and pointed with the best blue lias mortar.

The bed for the flagging both old and new, if any is required, to be made with proper earth, gravel, or dry rubbish, and all surplus earth and rubbish to be carted from the streets as it arises from the works.

The flagging to be properly cut and rebated to receive all area gratings, coal shoots, rain water troughs, &c.

Any damage done to gas or water service pipes in digging for the flagging, or in any way connected with the work, to be made good by the contractor, as also all and every other damage to windows, wood, or glass work; and the contractor will be held responsible for, and will make compensation for any injury that the public may sustain through the negligence of his workmen, or otherwise.

The whole of the flags to be of the very best quality, from Halifax, the quarries in the neighbourhood of Bradford or in Yorkshire, and subject to the approval of the surveyor.

The contractor to provide all lights and proper guards at night, and when old paving is to be taken up the work is to be done under the direction of the surveyor, and if considered necessary, the stones are to be removed from the streets to be re-faced and squared. No stone to be stacked in the streets.

The flagging to be measured after the work is completed.

The contractor to provide all stone, materials, tools, implements, horse and cart hire, and pay all railway dues, freightages, etc., and also to provide all labour of every kind for properly completing the work to the full and entire satisfaction of the surveyor. Payment will be made as the work proceeds, on the certificate of the surveyor.

Should the contractor fail to perform the work to the satisfaction of the surveyor, he then shall have power to execute the work and charge the same to the contractor, and deduct the cost from any amount that may be due to him; and in the event of the cost being more than the amount due, or if there shall then be no sum due to the contractor, such cost shall be paid by the contractor to the mayor, aldermen, and citizens, and the same shall be recoverable from him as liquidated and ascertained damages.

Caithness Flagging

is now used very largely instead of Yorkshire; it comes from Thurso in Scotland, and it is contended for it that it possesses many excellent qualities, amongst others may be enumerated the following:

(1). It is impervious to wet.

(2.) It is not slippery nor does it wear so.

(3.) It does not scale or flake.

(4.) It dries rapidly after rain.

(5.) Its appearance is cheerful.

(6.) Great durability, as it does not abrade.

(7.) Frost has no effect upon it.

(8.) Can be re-used when half worn.

(9.) Cleanliness; for, not being porous, no dirt or dust can adhere to it.

(10.) Vehicular traffic may be turned over it without injury to the path.

(11.) Economy; as natural forces can be used, thus saving labour, and it can be laid from 1¹/2 to 2 inches thick only.

(12.) Having sawn edges, the joints are expeditiously and well made.

(13.) Its whole surface wears evenly.

The following table was compiled by the well-known firm of Kirkaldy, by direction of Mr. Tarbotton the Borough Engineer of Nottingham, in order to ascertain the resistance to a gradually increased bending stress upon Yorkshire flagging as compared with Caithness.

Yorkshire.

Test No.	Weight.	Dimensions.					Ultimate Stress.
		Length.	Breadth.		Thick- ness.
K	lbs.	inches.	inches.		inches.		lb.
1918	184	36	24	·07	2	·46	4	·744
1919	163	36	24	·03	2	·22	3	·398
1920	107	36	23	·90	1	·50	1	·459
Mean	151	36	24	·00	2	·06	3	·200

Caithness.

Test No.	Weight.	Dimensions.					Ultimate Stress.
		Length.	Breadth.		Thick- ness.
K	lb.	inches.	inches.		inches.		lb.
1921	215	36	24	·06	2	·59	17	·274
1922	178	36	24	·05	2	·15	12	·711
1923	114	36	23	·90	1	·38	6	·211
Mean	169	36	24	·00	2	·04	12	·065

By which it appears that the balance in favour of Caithness flagging is 8·865 lbs.

The objection to this style of flagging is, that however varied the sizes of the stones selected may be, as they have sawn edges and are very hard to cut with a chisel, a difficulty sometimes arises in finishing rounded corners of footpaths, and against uneven frontages of shops or buildings abutting on the footpath; this is especially the case in old towns.

Blue Lias Flagging.

—A blue lias flagging does not make a first-rate pavement, as although it is very cheap, durable, clean, and has many other good qualities, it sometimes wears slippery and is then dangerous to pedestrians; but the Devonian limestone, which is much used in the west of England, has not apparently this defect.

Concrete Footpaths.

—These have been tried in this country, but generally without success; the concrete or cement cracks, and in addition to this the paths wear slippery and greasy, and as some time is necessary in order to allow the concrete to thoroughly set before the traffic can be allowed on them, they have not found much favour.

In the United States, however, concrete footpaths seem to be made successfully; the following detail particulars of such a foot-pavement will, I think, be of great interest and use.[107]

“Concrete footpaths should be laid upon a form of well-compacted sand, or fine gravel, or a mixture of sand, gravel and loam. The natural soil, if sufficiently porous to provide thorough sub-drainage, will answer.[108]

“It is not usual to attempt to guard entirely against the lifting effects of frost, but to provide for it by laying the concrete in squares or rectangles, each containing from 12 to 16 superficial feet, which will yield to upheaval individually, like flagging stones, without breaking and without producing extensive disturbance in the general surface.

“When a case arises, however, where it is deemed necessary to prevent any movement whatever, it can be done by underlying the pavement with a bed of broken stone, or a mixture of broken stone and gravel, or with ordinary pit gravel containing just enough of detritus and loam to bind it together. In high latitudes this bed should be 1 foot and upwards in thickness, and should be so thoroughly subdrained that it will always be free from standing water. It is formed in the usual manner of making broken stone or gravel roads already described, and finished off on top with a layer of sand or fine gravel, about 1 inch in depth, for the concrete to rest upon.

“The concrete should not be less than 3¹/2, and need rarely exceed 4 to 4¹/2 inches in thickness, the upper surface to the depth of ¹/2 an inch should be composed of hydraulic cement and sand only. Portland cement is best for this top layer. For the rest, any natural American cement of standard quality will answer. The following proportions are recommended for this bottom layer.

Rosendale or other American cement	1		measure
Clean sharp sand	2	¹/2	„
Stone and gravel	5		„

“It is mixed from time to time as required for use, and is compacted with an iron-shod rammer in a single layer to a thickness less by ¹/2 an inch than that of the required pavement. As soon as this is done and before the cement has had time to set, the surface is roughened by scratching, and the top layer, composed of,

1 volume of Portland cement, and
2 to 2¹/2 volumes of clean fine sand,

is spread over it to a uniform thickness of about 1¹/2 inch, and then compacted by rather light blows, with an iron-shod rammer. By this means its thickness is diminished to ¹/2 an inch. It is then smoothed off and polished with a mason’s trowel and covered up with hay, grass, sand, or other suitable material to protect it from the rays of the sun, and prevent its drying too rapidly.

“It should be kept damp and thus protected for at least 10 days, and longer if circumstances will permit; and even after it is opened to travel, a layer of damp sand should be kept upon it for two or three weeks, to prevent wear while tender.

“At the end of one month from the date of laying, the Portland cement mixture forming the top surface will have attained nearly one-half its ultimate strength and hardness, and may then be subjected to use by foot-passengers without injury.

“The rammers for compacting the concrete should weigh from 15 to 20 lb., those used on the surface layer from 10 to 12 lb. They are made by attaching rectangular blocks of hard wood shod with iron to wood handles about 3 feet long, and are plied in an upright position. Certain precautions are necessary in mixing and ramming the materials in order to secure the best results. Especial care should be taken to avoid the use of too much water in the manipulation. The mass of concrete, when ready for use, should appear quite incoherent, and not wet and plastic, containing water however in such quantities that a thorough ramming with repeated though not hard blows will produce a thin film of moisture upon the surface under the rammer, without causing in the mass a gelatinous or quicksand motion.”

Under the head of Concrete may be included many artificial stone pavements, such as “Bucknell’s Granite Breccia” “Ransome’s Artificial Stone,” “Eureka Concrete,” “Granolithic,” and the “Silicated Victoria Stone,” this last being worth a description. The stone is really a concrete, formed by mixing very superior Portland cement with crushed Thames gravel, furnace or iron slag, Kentish rag-stone, granite chippings, or other suitable material carefully washed. This fine concrete, after being mixed in the moulds forming the slabs, is thoroughly incorporated by being rocked or jiggled in a trembling machine; this motion, as can be easily understood, making the whole mass even and homogeneous when it sets. The cost of the slabs is about 9d. per square foot, 3 inches in thickness, and they make an excellent footpath.

Brick Footpaths.

—These are sometimes constructed of ordinary bricks laid on their sides, but soon wear, and are unsuitable for the purpose.[109] Staffordshire blue paving bricks make an excellent footpath. These are bricks made of stoneware highly vitrified; they should be about 12 inches in length by 6 inches wide, by about 27/8 inches in thickness, their surface being chequered with a diamond pattern so as to prevent their being slippery. They are exceedingly hard and durable if well burnt, and to ascertain this a brick should be broken across and the colour, etc., noted.

They should be laid in cement mortar upon a bed of concrete or sand. The objections to this class of pavement are as follows:

(1.) The colour is objectionable; being very dark, the footpaths give a street the appearance of mourning.

(2.) The difficulty of breaking up the path for gas or water services, or for other purposes.

(3.) The hardness of the bricks makes them awkward to cut to rounded corners, or for water trunks, coal-holes, etc.

(4.) A loaded hand-barrow driven over them will sometimes break off the chequered pattern.

(5.) They are slippery in a frost after snow.

But notwithstanding these disadvantages, they make a most wonderfully durable and useful pavement for back streets.

Granite Slab Pavement.

—This is sometimes adopted, large granite slabs, 6 inches in thickness being laid; they are very useful when there are cellars underneath, or where heavy vehicular traffic is intended to cross the foot pavement. Granite is of course excessively durable, but it wears very slippery with traffic and must then be tooled or axed; in process of time this wears it out, and its first cost is heavy.

This description of pavement can be laid with advantage in front of markets or similar buildings.

Artificial Asphalte Pavements.

—The cost of obtaining natural rock asphalte from the mines, and the knowledge that it is composed of two very simple ingredients, limestone and bitumen, has led to a great number of artificial asphaltes being introduced, especially for foot pavements. “British Rock Asphalte” is a name by which many of the compositions are known; “Beauchamp’s Mendip Mountain Machine-made Granite Asphalte” is a high-sounding title; “Prentice’s Mineral Foreign Rock Asphalte” is another.

All these, and many more of the same description, are really what may be better and more correctly described as “tar concrete” or “tar paving,” and consist of different modifications of the homely coal-tar and limestone.

So long ago as the year 1840, “Lord Stanhope’s Composition” was well known; it was made as follows:

Three gallons of Stockholm tar, 2 bushels of well-dried chalk, 1 bushel of fine, sharp, clean sifted sand, the whole being boiled in an iron caldron.

Tar paving is now made in many and various ways by different surveyors of towns, some making it with hot compositions, some with cold. A description will be found in the chapter on Macadamised Roadways, page 46, of one method of making it, a modification of this being all that is necessary for foot pavements.

The best paths of this description that I have seen are to be found at Torquay, and by the kind permission of Mr. John Little, County Surveyor of Devon, and late Surveyor of Torquay, I give his useful specification in detail, as follows:

Tar Concrete for Footpaths.

Proportions of Materials.

12	barrow	loads of	engine ashes.
4	„	„	screened slaked blue lias lime.
4	„	„	small spar or sharp grit.
34 gallons of best gas tar.
20 bucketsful, say 70 to 80 gallons of water.

Method of Mixing.

—On a clean flagged or wooden floor spread three barrow-loads of ashes, then about one barrow-load of lime, and so on until the whole of the dry materials (or one mixing) has been spread; then throw over them about three bucketfuls of tar, and before mixing it with them add (say) six bucketfuls of water; then mix as for concrete, and when the liquids are pretty well absorbed add a similar quantity, mix again, and so on until all the liquids have been absorbed; the mass will then be something of the consistency of ordinary mortar. Next pass the whole three times at least through a pug mill: if this be not done the concrete will be a failure. An ordinary hand pug-mill will not be sufficient; the knives are not strong enough, nor will it incorporate the materials thoroughly, but an upright pug-mill, worked by steam power where practicable, or by at least one horse, should be used.

It will be found that as the mass emerges from the pug-mill a large proportion of the water will run from it; means should therefore be provided for allowing the water to escape freely from the floor.

Method of Laying.

—Prepare the path for a layer of concrete 3 inches in thickness, on a hard dry bottom, inclining from the inside to the kerb, at the rate of ¹/2 an inch to a foot for pathways not more than 6 or 7 feet wide, but for wider pathways an inclination of ³/8 of an inch to a foot will be sufficient.

A template the full width of the path having been provided, lay concrete with a shovel on the inner side of the path for a length of (say) 15 feet and a width of 1 foot, at such a height that when it has been well rammed and patted with shovels it shall be the exact height intended for the path; this is to form a resting-place for one end of the template, the kerb forming that for the other end; then fill the intervening space with concrete up to the template, treading and ramming it solidly for about twenty minutes, and as it gets into shape, patting it with shovels and smoothing with a trowel; then, with an iron (not stone) roller weighing about 5 cwts., roll for two hours, trimming and filling up hollows where necessary; then go on with another length, and occasionally roll the first for half-an-hour, and so on. Experience alone will decide the quantity of rolling necessary after the first day or two, as weather and other causes tend to a more rapid solidification of the concrete at some times than at others.

On the third day, sprinkle a small quantity of sea or other very fine sand on the concrete, and allow it to remain for two or three days after the path has been in use—it should then be removed.

General Remarks.

—The ashes should not be those from a saw-mill or other place where wood ashes would be mixed with them. All ashes, spar or grit, and lime, should be passed through a screen of ³/8-inch mesh. The lime should be the best blue lias, slaked under cover; it should be allowed to lie for at least four days, but not more than six days, before it is used. The spar or grit should be sharp and angular.

Great care should be taken to keep the concrete free from mud or dust; it should be tipped from the carts or barrows, either directly into place, or, if this cannot be done, a few slabs or boards should be laid down, on which it may be tipped.

The path should not be used until the concrete is sufficiently solid to bear a man’s weight without taking the impression of his boots.

It has been found by experience that the laying of this concrete should not be commenced before May, and that it should not be continued beyond the end of September (or middle of October, if the weather is very fine). Frost is fatal to it before it has become hard, and continuous cold wet weather retards considerably the hardening.

There can be no doubt that a pavement of this description for traffic that is not too heavy answers every requirement; for streets of greater traffic, genuine mastic asphalte should be used.

Before closing my remarks on artificial asphalte pavements, the following description of an American method may be interesting:

On a dry foundation is placed a coat of rough clinkers from anthracite coal or iron clinkers from a foundry, mixed with sand and tar in the proportions of 15 cubic feet of fine sifted ashes, 14¹/2 cubic feet of pit sand, and 1¹/2 cubic feet or 9 gallons of tar. This is laid about 3 to 4 inches thick and well rolled. Over this is placed a coating from 1 inch to 1¹/2 inch thick, composed of 15 cubic feet of coarse sifted ashes, 15 cubic feet of clinkers, and 1¹/4 cubic feet or 8 gallons of tar. It must be then well rolled and sanded, care having been taken that the materials are thoroughly mixed.

Gravel Footpaths.

—For the suburbs of a town and in the country, nothing looks so pretty as a gravel footpath.

The same rules that apply to a macadamised roadway apply to a gravel footpath. They must be well “bottomed,” and well drained and well rolled. Limestone or other stone chippings may with advantage be used with a pit gravel for constructing paths of this description, and a barrelled surface looks better and is more enduring than a hanging path. The following cross sections of footpaths will explain themselves better than any long description:

Gravel footpaths are sometimes tarred over when thoroughly consolidated. This must be done only when the weather is quite settled and fine: the least rain will spoil the whole operation; it consists in simply tarring over the surface of the footpath in the same manner that a gate or wall or any other substance would be tarred. The surface of the path must previously have been swept perfectly clean, and immediately as the tarring is completed, fine stone dust must be sprinkled on its surface; the traffic should be diverted from it for a few hours, and it is then ready.

Care must be taken that the tar is not too thin in consistency, and that the coat is not put on too thick. Treating a path in this manner saves gravel, which is washed or kicked off it if left with an ordinary surface; but a cold night, a slight shower, or inferior tar will make the whole process abortive, and the path will be in a fearful mess in the winter.

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