The raw materials used for the manufacture\nof cement consists mainly of lime, silica, alumina and iron oxide.<\/p>\n\n\n\n
Following table shows the approximate oxide\ncomposition limits of ordinary portland cement.<\/p>\n\n\n\n
Oxide<\/strong><\/p>\n\n\n\n (1)Lime \u2013 CaO -60 \u2013 67%<\/p>\n\n\n\n (2) Silica-SiO-17-25%<\/p>\n\n\n\n (3)\nAlumina – Al O-03-08%<\/p>\n\n\n\n (4) Iron oxide-Fe2Oa-0.5-06%<\/p>\n\n\n\n (5) Magnesia \u2013 MgO-0.1-04%<\/p>\n\n\n\n (6) Sulphur-S-01-03%<\/p>\n\n\n\n (7)\nAlkalies -KO Na 0. 04-13%<\/p>\n\n\n\n (8) Gypsum \u2013 Caso-4%<\/p>\n\n\n\n Chemical\nrequirement:<\/strong><\/p>\n\n\n\n (a) Ratio of % of lime to % of silica,\nalumina and iron oxide when calculated by CaO-0.7 SO, should not exceed 1.02<\/p>\n\n\n\n 2.8 Si O, + 1.2 L-O, + 0.65 Fe; O, less\nthan 0.65 <\/p>\n\n\n\n (b) Ratio of of alumina to that of iron\noxide < 0.66%<\/p>\n\n\n\n (c) Free Insoluble residue <\/p>\n\n\n\n (d) Free Magnesia <5% <\/p>\n\n\n\n (e) Total sulphur content, calculated as\nsulphuric anhydride < 2.75%<\/p>\n\n\n\n (1)\nLime (Cao)<\/strong> : Important ingredients of cement and\nproportion is maintained Excess lime makes the cement unsound and to expand\nwhich results disintegration. Deficiency of lime decreases the strength of\ncement and causes cement to set quickly<\/p>\n\n\n\n (2)Silica\n(SiO)<\/strong> :- Important ingredients impart strength to\ndue to formation of calcium and tricalcium silicates Excess silica Increases\nthe strength of cement but setting time cement<\/p>\n\n\n\n (3)\nAlumina (AI2, O3):-<\/strong> It imparts quick setting\nproperty to cement, It acts as a flux. i.s. it lowers the clinkering\ntemperature Excess alumina weaken the cement.<\/p>\n\n\n\n (4)\nCalcium Sulphate (CaS04) Gypsum :-<\/strong> Its main\nfunction is to increase the initial setting time of cement.<\/p>\n\n\n\n (5)\nIron Oxide (Fe2O3 )<\/strong> : This ingredient imparts\ncolour, hardness and strength to cement.<\/p>\n\n\n\n (6)\nMagnesia (MgO)<\/strong> : It imparts hardness and colour to\ncement. A high content of magnesia makes the cement unsound.<\/p>\n\n\n\n (7)\nSulphur (S) :-<\/strong> Very small amount is useful in\nmaking cement sound.<\/p>\n\n\n\n (8)\nAlkalies :-<\/strong> The Alkalies present in raw materials\nare carried away by fuel gases during heating and cement contains only a small\namount of alkalies. Excess Alkalies cause a number of troubles such as alkali\naggregate reaction, efflorescence and staining. When used in concrete and as\nmortar Harmul constituents of cement are alkali oxides.<\/p>\n","protected":false},"excerpt":{"rendered":" The raw materials used for the manufacture of cement consists mainly of lime, silica, alumina and iron oxide. Following table shows the approximate oxide composition limits of ordinary portland cement. Oxide (1)Lime \u2013 CaO -60 \u2013 67% (2) Silica-SiO-17-25% (3) Alumina – Al O-03-08% (4) Iron oxide-Fe2Oa-0.5-06% (5) Magnesia \u2013 MgO-0.1-04% (6) Sulphur-S-01-03% (7) Alkalies […]<\/p>\n","protected":false},"author":1,"featured_media":1228,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[357],"class_list":["post-1227","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-civil-engineering","tag-cement"],"_links":{"self":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/posts\/1227","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/comments?post=1227"}],"version-history":[{"count":1,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/posts\/1227\/revisions"}],"predecessor-version":[{"id":1229,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/posts\/1227\/revisions\/1229"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/media\/1228"}],"wp:attachment":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/media?parent=1227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/categories?post=1227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/tags?post=1227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}