t [
M 0 R
2Jy
M OR
ei-«.
Hill]
lll ' X: ur/ )U ] ZZ °' ana or trass > to form an hydraulic mortar; ther nt e jj e ' s 10 uld be made extemporaneously, and must at anyPortion ^ about t0 be applied. Sometimes a pro-
file tr ag common sand mortar instead of lime is mixed with^ hoai'g the hydraulic cement hardens too soon, as in
c< Jnci S, t lt ' s , a P t t0 crack ; it is better when it takes 8 daysWe, e ; -Through the agency of the water, silicates ofHiy}/ 1£Una > (magnesia,) and oxide of iron, are formed,li esiae SU t I j ne a stor ‘y hardness.
e *trtl ly C( 1 le above two volcanic products, other nativefi‘is i 1(ia 0 , ,n i l0un< ls are used in making water cements. ToPer C(Jn j he'long all limestones which contain from 20 to 30°1 th e c a an< ^ s lb ca> By g ent le calcination, a portionHli tli e ai ,| >0,1 ' c ac ‘^ * s expelled, and a little lime is combinedC ' ut ed witl r ’ w *‘‘* e a silicate of clay and lime results, asso-^btiihr ] 1 llIue in a subcarbonated state. A lime-marl con-P r >'j U(jj C( . S . S will bear a stronger calcining heat without
•‘Iso (Je D 5* ’ ts qualities as a hydraulic cement ; but much^‘ysical n< 8 u l’ 011 the proportions of silica present, and theIn £, ) S }, ructur e of all the constituents.”instancy an ^> ' y bat is commonly called cement-stone, is thei fou nd « fer ‘erall y used for making this kind of mortar.Hs 0 f g, 1 ln great abundance on the coasts of Kent, in theStui| es var' e ^ e ^- an< ^ Thanet, and various other places. Theyellow n m S * Ze ^ roln that of a fist to a man’s head, are of° ‘ale s or brown colour, interspersed with veins
t) ^‘e foi}’ .^l le ' r specific gravity is 2.59.
cem e ° Wln g analyses of several cement-stones, and of° bei'thiJ 1 t“ a( lc with them, is taken from the works*’ b’avy, and others—
A. Q
^bonjjt ^( y^fttecement stones
- magnesia
Protoxide of iron"manganese .
r l **on.
°yt«e,, ts ofthe
.
cement.
Hi,
">a,
No. 1.
No. 2.
No. 3.
No. 4.
No. 5.
65.7
61.6
82.9
63.8
05
6.0
1.6
6.0
—
} A’ 3
15
11.6
18.0
15.0
—
13.0
14.0
6.6
4.8
—
trace.
5.7
—
3 0
—
_
—
1.2
6.6
—
—
3.4
55.4
54.0
55.0
56.6
—
—
—
—
1.1
36 0
31.0
38.0
_
21.0
8 6
15.0
13.0
—
13.7
The
<la,.i^’ and n ! f re ' n t ^ 1IS country calcined in kilns, ground,w ,.; 1 1 dolte d —
. ,n casks. The colour of the powder is a'H,/ Hen J^ 1 . a t ‘"S e °f red. It absorbs very little
lw e 'Jaii )0 . nia .^ e '. nto paste, and soon hardens. Immediatelyr p,°? , tioiia i e ” lt; *' s mixed with sharp sand in
,, Hig
"ti^ U . t 'l i| ne nt g OS . it!on is employed in all marine and river-y ari 0 ,iJ 111 .f 1 ' 6 Votings of walls in damp situations,mted, us other ' '
'Hit!
al.
purposes to which common mortar is
)a t}jj es > tha/**/”^’ blending, and Beating of; M. Felibien’a t| 1(! P‘'oces s 0 f' e anc ’ ent masons were so very scrupulousI “Hq ^“birin- r P r °perly mixing and blending the materialsj f e ' n ploy e °j n ‘ orta r, that the Greeks kept ten men con-I *'b'Hv' 1 ^ erei l tl ' °* a l° n " space of time, to each bason;| '' l| ll g lUs tells 16 rnor ‘ar of such prodigious hardness, thatI ! l j lil Xif n 8< ' lv ed 1 us pieces of plaster falling off from old! 'mute • ol J 1111 * 6 ta bles, Felibien adds, that it was a
1 11 Vv ' t b th masons t0 their labourers, that they should
N.. e sweat of their brow, i.e., labour at it a long
time, instead of drowning it with water to have done thesooner.
In modern practice, when the buildings are of considerablemagnitude, the mortar is usually ground in a mill; but which-ever way made, it may be laid down as a fixed rule, that themore labour there is bestowed on the mixing and thoroughlyblending the mortar, the harder and better will it be, and, asa necessary consequence also, so much more perfect will bethe work in which it is used.
The following excellent observations on the advantages ofbeating mortar, are taken from Mr. Weale’s useful littlework, “ Dictionary of Terms of Arts.”
“ Mortar contained in a mould may be beaten or rammedin the manner of pis4, ‘a mode of building formerly in use,whereby walls were formed by ramming and beating downearth, clay, &c., between upright planks,’ and acquires bythat means great compactness ; but an increase of resistancedoes not always result^from it.
“ In order that any material be beaten with effect, it isnecessary that it should possess a certain degree of consis-tency, which is a mean between complete pulverulence andthat state of ductility which constitutes a firm paste. Nocompression is possible, when the material escapes fromunder the rammer; and this is still practised by the buildersin pise, who never employ any but earth slightly moistened.Mortar may always be prepared in this way, leaving it, afterit has been worked in the ordinary manner, to undergodesiccation to a proper extent.
“ The successive approximation of the particles of thecompressed material to one another, necessarily determinesa foliated structure, which, though it may not be perceived,is nevertheless real. Analogy will lead to the conclusion,that in every possible case, a body thus formed ought tooppose a greater resistance to a tractile force, in proportionas its direction forms a smaller angle with the plane of thelaminae ; however, experience shows that this in general doesnot take place. The following has been determined in thisrespect :—
“ 1st. Beating has the effect of augmenting the absoluteresistance of mortars of rich limes and pure sand in everycase, but in an unequal manner. The greatest resistanceassumes a direction perpendicular to the planes of the laminse,when the mortars are buried in a damp soil immediately aftertheir fabrication. It remains parallel to these same planes,when the mortars have been exposed to the atmosphericinfluence.
“2nd. The effect of beating is not constantly useful tomortars of hydraulic or eminently hydraulic limes, and cal-careous or quartose sands or powders, except in the casewhen these mortars are used under a damp soil. The greatestresistance is then in a direction perpendicular to the planesof these lamin®, as with the mortars of rich limes; but inthe air the superiority of the mortars which have been beaten,over those which have not, is only exhibited in one direction,and that is parallel to the plane of the laminae.
“ 3rd. Beating becomes injurious in every case, when thehydrates of the hydraulic or eminently hydraulic limes areemployed without admixture, and subjected to the influenceof a damp soil ; and is favourable to it only in the directionparallel to the laminae, when the stuff dries in the air.”
Mortar, White, used in plastering the walls andceilings, is made of ox or cow’s hair mixed with limeand water, without any sand. The common method ofmaking this mortar, is one bushel of hair to six bushelsof lime.
Mortar, used in making water-courses, cisterns, &c., ismade of lime and hogs’ grease, sometimes mixed with the