Pumice-plank and pumice-panel homes are houses made of prefabricated members. After laying the foundation, the individual members mainly the wall members are prepared and used to erect the house on the foundation slab. This mode of construction is expecially well-suited for collective self-help measures in which several families wish to build the same kind of house, because erection of the plank or panel walls requires the work of several people at once Fig.
One of the main advantages is the comparatively short erection time. Pumice-concrete brick houses are built in a similar manner to heavy-clay brick houses, i. This method yields very individual homes and serves well for renovating or expanding existing homes. Building with Pumice 2.
General Information on Pumice 2. Figure 5: A volcanic eruption In addition to light-colored pumice, there are also various dark-colored forms referred to as lava, tuff, etc. Pumice has the following chemical composition: silica SiO 2 approx.
Figure 6: Pumice deposits on the downwind side of a volcano The average deposit is loose, with a layer thickness ranging from 50 to cm. Pumice has excellent properties. As a building material it is Figure 8: Pumice extraction -very light, -inexpensive, -refractory, -resistant to pests, -easy to work with, -sound-absorbent, -heat-insulating, -temperature-balancing Figs.
But then, it also has some negative properties like: -the lower compressive strength of pumice concrete, as compared to concrete containing other, heavier aggregates; -the tendency of its edges and corners to break off more easily than those of heavy concrete' -its lack of frost resistance when wet. Consequently, pumice building material should not be used for: -foundations, -components with constant exposure to water, e. Colors include white, gray, blue, cream, green, and brown.
The pores or vesicles in the rock take two forms. Some vesicles are roughly spherical, while others are tubular. Probably the most significant property of pumice is its low density. Pumice tends to be so light that it floats on water until its vesicles fill and it eventually sinks. Before it sinks, pumice can float for years, potentially forming huge floating islands. Pumice rafts from the eruption of Krakatoa drifted around 20 years. Pumice rafting disrupts shipping and is important in the dispersal of marine organisms to new locations.
Pumice occurs in everyday products and has many commercial uses. Stone-washed jeans are made by washing the denim with pumice rocks. The Greeks and Romans rubbed the rocks on their skin to remove unwanted hair. Because the rocks retain water, they are valued in horticulture to grow cacti and succulents.
Ground pumice is used as an abrasive in toothpaste, polishes, and pencil erasers. Some types of chinchilla dust bath powder consists of pumice powder. The powder is also used to make cement , filter water, and contain chemical spills. Any violent volcanic eruption may produce pumice, so it is found worldwide. Italy and Turkey led production in , mining 4 million tonnes and 3 million tonnes, respectively.
Pumice and scoria are two similar, commonly-confused igneous rocks. Italy is the largest producer of pumice in the world. The other top five leading pumice producers are Spain , Greece, Turkey, and Chile. Pumice is also mined extensively in the United States , with Oregon, Arizona, and California being especially major producers of the rock in the country.
Pumice mining has a lower impact on the environment than other rocks and minerals. Extracting pumice usually involves surface mining procedures, where the top soil layer is simply removed to get to the deposits, and the soil is stored for later reclamation of the mining site following the cessation of operations.
The pumice layer is then scraped or ripped out, and subjected to crushing for producing "mine grade" pumice. This mine grade produce is then transported to the plant for additional processing. Drying procedures at the plant removes moisture from pumice to favorable levels so that it may undergo further refining.
The mined rock is then passed through further processes involving crushers, shakers, and screens to produce "industrial grade" pumice. Further processing still is often needed to meet the standards for other commercial applications, such as in the cosmetics industry. So it's a way to renew ecosystems somewhere, but it also can introduce invasive species," Dr Jutzeler said. If it reaches Australia, that could be a boon for the damaged Great Barrier Reef, some experts say.
Coral regeneration has collapsed in the world's largest reef system following unprecedented bleaching events in and Rise and fall of marine volcano. Deep sea volcanoes found off Sydney. This video can not be played To play this video you need to enable JavaScript in your browser.
Sailors Tom Whitehead and Shannon Lenz said the floating rocks left "no water visible". Sailor Michael Hoult was one of the first to report the volcanic rock raft.
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