Tímarit Verkfræðingafélags Íslands - 01.01.1916, Page 11

7
or chinks sliall appear in it, nor the pat warp, The
test is complete in 28 days, but as a rule these
marks appear in 3 days.
The Le Chatelier test is also valid for this purpose.
IV.
rJ'he cement sliall be so /inely ground, that wlien
sifted on a sieve 900 meshes per square centimeter
(5776 meshes per square inch), the residue shall not
exceed 3 per cent.
The diameter of the wire sliall be equal to half
a mesh.
V.
For lesling its strength, the cement sliall be mixed
with sand, one part by weight of cement to three
parts by weight of sand, this mixture shall be gauged
with water, as a rule 8—9 per cent by weight.
Outof the mixture, cubic briquettes 50 square centi-
meter shall be moulded. German or english slandard-
sand is to be used.
The first 24 hours, the briquettes are to be kepl
in moist air, and tlien put into water. Briquettes
of cement of tlie ordinarv selting time shall stand a
pressure of 200 kilogrammes pr. stiuare centimeter
(2844,5 Ibs per square inch) after a lapse of 28 days.
No less tlian 5 briquettes are to be tested and the
average stress of these is to be considered as the
real pressure strenglh of the cement.
In making the briquettes, the mixture shall be
compressed by means of Dr. Böhmes bammer
apparatus. 150 slrokes shall be dealt to the briquette
in the mould by this hammer, the weiglit of which
is 2 kilogrammes.
4. Stoíhanir og fjelög, sem Yerkfræðingafjelag íslanils liefur skiftisaniband við.
Islensk: Hagstofa íslands.
Búnaðarfjelag íslands.
Fiskifjelag ísands.
Dönsk: Dansk Ingeniörforening.
Den tekniske Forening.
Akademisk Architektforening.
Industriforeningen í Köbenliavn.
Norsk:
Sœnsk:
Finsk:
Pýsk:
Austnrrilcsk:
Den norske Ingeniör- og Arkitektfore-
ning.
Svenska Teknologföreningen.
Tekniska Föreningen í Finland.
Verein Deutscher Ingenieure.
Österreichiselier Ingenieur- und Archi-
tekten-Verein.
5. Fjelagaskrá 31. desember 1915.
Á s g e i r T o r f a s o n , cand. polyt., efnaverkfræð-
ingur.
B e n e d i k t J ó n a s s o n, verkfræðingur.
Forberg, O., landssímastjóri, r. af dbr.
Hlíðdal, Guðm. J., verkfræðingur.
Jessen, M. E., vjelfræðiskólastjóri.
Jón Isleifsson, verkfræðingur.
Jón Þorláksson, cand. polyt., landsverkfræð-
ingur.
Kirk, N. P., cand. polyt., verkfræðingur.
Krabbe, Th. H., cand. polyl., landsverkfræð-
ingur.
Ólafur Þorsteinsson, cand. polyt., verk-
fræðingur.
Rögnvaldur Ólafsson, byggingameistari.
Smith P., símaverkfræðingur.
Thoroddsen, Sig., cand. polyt., bæjarverk-
fræðingur, adjunkt við mentaskólann.
Zirnsen, K., cand. polyt., borgarstjóri Reykja-
víkur.
Zoega, Geir, G., cand. polyt., verkfræðingur.
Þórarinn Kristjánsson, cand. polyt., verlt-
fræðingur.
Allir í Reykjavík.
2