In 1890 Portland cement works were built, and there is a large trade in timber.
The remaining silicates and aluminates present, and ferric oxide and magnesia, if existing in the moderate quantities which are usual in Portland cement of good quality, are of minor importance and may be regarded as little more than impurities.
The quality of Portland cement is ascertained by its analysis and by determining its specific gravity, fineness, mechanical strength Tesfing.
The use of trass in this manner as an adjunct to Portland cement has been advocated by W.
The quantity of Portland cement made in Ohio increased from 57,000 barrels in 1890 to 563,113 barrels in 1902 and to 1,521,764 barrels in 1908.
This, if the dam had been thoroughly well constructed, either with hydraulic lime or Portland cement mortar, would have been easily borne.
Good Portland cement is so much stronger than any lime that there are few situations where it is not cheaper as well as better to use the former, because, although cement is the more expensive matrix, a smaller proportion of it will suffice for use.
At one time Portland cement concrete was considered to be lacking in fireproof qualities, but now it is regarded as one of the best fire-resisting materials known.
The precise mechanism of the process of setting of Portland cement is not known with certainty, but it is probably analogous to that of the setting of plaster of Paris, consisting in the dissolution of the compounds produced by hydration while they are in a more soluble form, their transition to a less soluble form, the consequent supersaturation of the solution, and the deposition of the surplus of the dissolved substance in crystals which interlock and form a coherent mass.
Marl is found in the south part of the state; limestone most largely in the north part of the lower peninsula, and the east part of the upper peninsula; and the production of Portland cement increased rapidly from 77,000 barrels in 1898 to 3,572,668 in 1907.