Portland Concrete Quotes

2. The total percentage of C2S and C3S in all types of Portland cements is around 70 per cent, so that even though the strength development of two cements at early stages may be different, the final strength obtained after long periods of time may not be different. However, removal of formwork, prestressing of concrete depends to a large extent on the early strength of concrete. 3. When producing low-heat Portland cement the percentage of C2S is increased and that of C3S and C3A is decreased. This type of cement is of particular use in construction of dams, massive foundation, etc. to reduce the production of heat. 4. Reducing C3A increases sulphate resistance but the 7 day and 28 day strengths also get lowered as compared to the ordinary Portland cement. Sulphate-resisting Portland cement has less than 5% C3A. This type of cement is recommended for sewer works. 5. Rapid hardening cements compared to ordinary cements have more or less the same composition except that the latter is more finely ground and may sometimes contain higher percentage of C3S. The increased fineness increases the 7 day strength.

Ransome, a trim and stern-faced fellow, arrived in San Francisco in the early 1870s. It was an excellent place and time for an ambitious, inventive type. Grown rich from the Gold Rush, the city was by then a hub for the new Silver Rush in nearby Nevada, and a base for moguls of the mining, manufacturing, and railroad industries. It was growing fast; the population quadrupled between 1860 and 1880 to nearly a quarter of a million.23 Ransome found a job at a company that produced concrete blocks for paving stones and architectural decorations,24 and talked his colleagues into switching over to his father’s brand of cement. Within a few years, he left to start up his own outfit. He sold concrete vases and cement components (he eventually abandoned his father’s brand for the standard Portland cement), and in his spare time noodled around trying to develop new reinforcing techniques that would make stronger, more durable, more versatile concrete.