{"id":384535,"date":"2021-01-13T17:59:22","date_gmt":"2021-01-13T12:29:22","guid":{"rendered":"https:\/\/shyamsteel.com\/?p=384535"},"modified":"2021-01-13T17:59:39","modified_gmt":"2021-01-13T12:29:39","slug":"different-type-of-curing-methods-in-concrete-construction","status":"publish","type":"post","link":"https:\/\/shyamsteel.com\/blogs\/different-type-of-curing-methods-in-concrete-construction\/","title":{"rendered":"Different Type of Curing Methods in Concrete Construction"},"content":{"rendered":"\n

Curing <\/strong>is\nthe process to control moisture loss during hydration of cement. Hydration\ntakes time \u2013 days, or even weeks rather than hours. To achieve its potential\nstrength and durability, curing needs to be done for an ideal period of time. <\/p>\n\n\n\n

Purpose of Curing<\/u><\/strong><\/p>\n\n\n\n

The reaction between cement and water is called\u00a0hydration. It is an exothermic reaction (which releases heat). After adding water to the concrete mix, hydration starts, which tends to dry the concrete quickly. Hence concrete is kept moist by curing, to stop it from drying out before attaining its maximum strength.<\/p>\n\n\n\n

The factors required for curing of the structural elements are:<\/u><\/strong><\/p>\n\n\n\n

  1. Specified Strength of Concrete<\/li>
  2. Grades of concrete<\/li>
  3. Temperature – The chemical reaction between cement and water in concrete releases heat, which requires constant adding of water to complete hydration. In summer fifty percent of water is evaporated. So, more water is needed during sunny days.<\/li>
  4. Size and Shape of the Concrete member<\/li>
  5. Economy<\/li>
  6. Material availability<\/li>
  7. Labor force<\/li>
  8. in situ versus plant concrete production<\/li>
  9. Aesthetics<\/li><\/ol>\n\n\n\n

    Curing Methods<\/strong><\/h2>\n\n\n\n

    Curing methods can be classified into three basic methods<\/p>\n\n\n\n

    • Water Addition Method<\/strong><\/li><\/ul>\n\n\n\n

      This method keeps the surface of the concrete moist by ponding, spraying\/sprinkling, fogging, misting, wet burlap, and other water absorbent materials <\/p>\n\n\n\n

      • Water Retention Method<\/strong><\/li><\/ul>\n\n\n\n

        This method prevents loss of moisture from the concrete by covering it with polythene sheeting or leaving the formwork in places<\/p>\n\n\n\n

        • Temperature control Method:<\/strong><\/li><\/ul>\n\n\n\n

          This involves live steam, heating coils, electrically heated forms or pads<\/p>\n\n\n\n

          Considerations for selecting a curing\nmethod:<\/strong><\/strong><\/p>\n\n\n\n

          a) <\/strong>The type of construction such as those involving large horizontal surface areas as in roads, floors, and airfields, or, those involving\u00a0formed concrete\u00a0in walls, columns,\u00a0beams, cantilevers, and arches, etc<\/p>\n\n\n\n

          b)<\/strong> The place of\nconstruction, whether indoors and damp situations (as inside a building) or\noutdoor<\/p>\n\n\n\n

          c)<\/strong>\u00a0The weather conditions where concrete is being laid in cold climates or in dry and hot weather<\/p>\n\n\n\n

          The methods in detail:<\/strong><\/p>\n\n\n\n

          Water Addition Method<\/strong><\/u><\/h3>\n\n\n\n

          Water addition is considered as the best method of curing of concrete as it satisfies all the requirements of curing – absorption of the heat of hydration, promotion of hydration, and elimination of shrinkage. Water curing is carried out by adding water to the surface of concrete to ensure that it is kept continuously moist. The water used for this purpose should not be more than about 5\u00b0C cooler than the concrete surface. Spraying warm concrete with cold water may give rise to \u2018thermal shock\u2019 that may contribute to cracking. <\/p>\n\n\n\n

          Water curing can be done in the following ways:<\/p>\n\n\n\n

          i.<\/strong> Spraying or Fogging.<\/p>\n\n\n\n

          ii.<\/strong> Ponding.<\/p>\n\n\n\n

          iii.<\/strong> Wet covering.<\/p>\n\n\n\n

          iv.<\/strong>\u00a0Immersion.<\/p>\n\n\n\n

          i. Spraying of Water:<\/h4>\n\n\n\n

          This method is ideally suited for almost all types\nof construction in most conditions. Vertical reclining walls, plastered\nsurfaces, concrete columns, etc. are cured by spraying water. It involves\nspraying water with the help of house pipes connected to\nthe main water supply lines. However in tall structures, water\nspraying at top levels may hamper work on the lower floors.<\/p>\n\n\n\n

          ii. Ponding of Water:<\/h4>\n\n\n\n

          Ponding is a\nquick, inexpensive and effective form of curing when there is a ready supply of\ngood \u2018dam\u2019 material (e.g. clay soil), a supply of water, and the \u2018pond\u2019 does\nnot interfere with subsequent building operations.<\/p>\n\n\n\n

          In this method, pavement slabs, roof slabs, etc.,\nare kept under water by making small ponds. It is the next common method of\ncuring of concrete suited best for horizontal surface areas such as roads,\nfloors, and slabs.<\/p>\n\n\n\n

          Small ponds, not more than 5 cm deep, are made over\nthe surface by raising temporary barriers.<\/p>\n\n\n\n

          These ponds are kept filled with water for several\ndays. In hot weather, ponding is the ideal method of curing of concrete.\nIt\nhas the added advantage of helping to maintain a uniform temperature on the\nsurface of the slab<\/p>\n\n\n\n

          iii. Wet Coverings:<\/h4>\n\n\n\n

          In some cases, wet coverings such as wet gunny bags,\njute matting, and straw are wrapped to the vertical surface for keeping the\nconcrete wet.<\/p>\n\n\n\n

          For horizontal surfaces, sawdust, earth or sand are\nused as wet coverings to keep the concrete in a damp condition for a longer\ntime.<\/p>\n\n\n\n

          Another method, suitable for flat, columnar, and vertical surfaces\n(after the formwork is removed) is covering the surface with\nstraw, burlap, hessian or jute soaked in water. These are kept moist for the\nentire period of curing. Fabrics are particularly useful on vertical surfaces since they\nhelp distribute water evenly over the surface and even where not in contact\nwith it, will prevent the surface evaporation from\nwithin the concrete and supply the additional water required for hydration.<\/p>\n\n\n\n

          iv. Immersion:<\/h4>\n\n\n\n

          The precast concrete items are usually immersed in curing tanks for a specific duration.<\/p>\n\n\n\n

          Water Retention Method by Curing Compounds(Membrane Method)<\/strong><\/h3>\n\n\n\n

          This may be broadly described as the chemical method\nof curing of concrete.<\/p>\n\n\n\n

          In this method, some suitable chemical compounds dissolved in\nsolvents are sprayed over the fresh concrete to be cured. The solvent evaporates, leaving behind a thin\nfilm of the chemical compound spread over the concrete surface.<\/p>\n\n\n\n

          This film prevents evaporation from the concrete.<\/p>\n\n\n\n

          Thus, if enough water has already been added at the time\nof preparation of concrete, it will set and\nharden nicely without much addition of water. The thick film of chemical\ncompound starts peeling off after some time (2-4 weeks) leaving behind the\nproperly cured concrete. Most curing compounds consist of different types of\nresins.<\/p>\n\n\n\n

          A major disadvantage of this method is that\ncontinuous concreting is not possible. The cured surface will not bond\nfirmly with a new layer unless the chemical is completely removed from it.<\/p>\n\n\n\n

          Still, on flat surfaces of single thickness, the\nmembrane method is used extensively.<\/p>\n\n\n\n

          Temperature control Method<\/strong><\/h3>\n\n\n\n

          The development of the strength of concrete is a\nfunction of not only time but also of temperature.<\/p>\n\n\n\n

          When concrete is subjected to a higher temperature,\nit accelerates the hydration process which results in faster development of\nstrength.<\/p>\n\n\n\n

          The exposure of concrete to higher temperature is\ndone in the following manners:<\/p>\n\n\n\n

          i.<\/strong> Steam curing at ordinary temperature<\/p>\n\n\n\n

          ii.<\/strong> Steam curing at high temperature<\/p>\n\n\n\n

          iii.<\/strong> Curing by infrared radiation<\/p>\n\n\n\n

          iv.<\/strong> Electrical curing<\/p>\n\n\n\n

          \u00a0i. Steam curing at ordinary temperature<\/u><\/h4>\n\n\n\n

          This method is mostly adopted for prefabricated\nconcrete elements; application of steam to construction will be a difficult\ntask. For steam curing, the concrete elements are stored in a chamber. The\nchamber should be large enough to hold a day\u2019s production.<\/p>\n\n\n\n

          The door is closed, and steam is applied, either\ncontinuously or intermittently. Accelerated hydration takes place at this\nhigher temperature and concrete attains the 28-day strength in about 3 days.<\/p>\n\n\n\n

          In large prefabricated factories, they have tunnel\ncuring arrangements. However, concrete subjected to a higher temperature at the\nearly period of hydration is found to lose some of the strength at a later\nstage.<\/p>\n\n\n\n

          Very fresh concrete should not be subjected suddenly\nto high temperature. A certain delay period after casting the concrete is\ndesirable.<\/p>\n\n\n\n

          ii. Steam curing at high temperature and pressure<\/u><\/h4>\n\n\n\n

          Unlike ordinary steam curing, this curing is carried\nout in a closed chamber. The super-heated steam at high temperature and high\npressure is applied to the concrete. This process is also called \u2018autoclaving.\u2019<\/p>\n\n\n\n

          The following advantages are derived from this\nprocess:<\/p>\n\n\n\n

          a.<\/strong> In one day or less the concrete develops the strength that\nnormally cured concrete gains in twenty-eight days. Also, it does not lose\nstrength at a later stage.<\/p>\n\n\n\n

          b.<\/strong> This concrete shows higher resistance to sulfate attack,\nfreezing & thawing action and chemical action.<\/p>\n\n\n\n

          c.<\/strong> High-pressure steam cured concrete shows lower drying\nshrinkage and moisture movement.<\/p>\n\n\n\n

          \u00a0iii. Curing by infrared radiation<\/u><\/h4>\n\n\n\n

          Curing of concrete by infrared radiations has been\npracticed in very cold climatic regions of Russia.<\/p>\n\n\n\n

          \u00a0iv. Electrical curing<\/u><\/h4>\n\n\n\n

          Another method of curing concrete, which applies\nmostly to very cold climatic regions, is using electricity. This method is not\nlikely to find much use in ordinary temperatures due to economic reasons.<\/p>\n\n\n\n

          What is the Right Time for Concrete Curing?<\/strong><\/h3>\n\n\n\n

          The right time for concrete curing depends on several factors.\nLike, temperature, the evaporation rate, moisture content in the air, etc.<\/p>\n\n\n\n

          According to ACI-308, three phases of concrete\ncuring should be done.<\/p>\n\n\n\n

          (1) Initial Curing.<\/h3>\n\n\n\n

          This process is also called Bleeding of Concrete. <\/p>\n\n\n\n

          After placing of concrete, the water starts bleeding\nfrom concrete and rises from its pores. After rising of water, evaporation takes\nplace, and the water starts disappearing from the surface due to evaporation.<\/p>\n\n\n\n

          Bleeding of concrete depends on many factors like\nthickness, length, temperature, etc. So, to reduce the loss of water and\nprevent shrinkage, initial curing of concrete is required. Evaporation reducers\ncan be used for this process.<\/p>\n\n\n\n

          (2) Intermediate Curing of Concrete.<\/h3>\n\n\n\n

          This process is done when finishing work is finished\nbefore the final setting of cement. It is required as water plays an important\nrole in the strength of concrete.<\/p>\n\n\n\n

          (3) Final Concrete Curing.<\/h3>\n\n\n\n

          After the final setting of concrete, it should be\ncured so that one can prevent the loss of more water and increase the strength\nof concrete.<\/p>\n","protected":false},"excerpt":{"rendered":"

          Curing is the process to control moisture loss during hydration of cement. Hydration takes time \u2013 days, or even weeks rather than hours. To achieve its potential strength and durability, curing needs to be done for an ideal period of time. Purpose of Curing The reaction between cement and water is called\u00a0hydration. It is an […]<\/p>\n","protected":false},"author":5,"featured_media":384536,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"wds_primary_category":0,"footnotes":""},"categories":[10],"tags":[28,119,15,120,117,121,118],"class_list":["post-384535","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blogs","tag-best-tmt-bar","tag-best-tmt-bar-for-construction","tag-best-tmt-bar-in-west-bengal","tag-concrete-curing-methods","tag-curing-in-concrete-construction","tag-different-type-of-concrete-curing","tag-methods-of-concrete-curing"],"_links":{"self":[{"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/posts\/384535","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/comments?post=384535"}],"version-history":[{"count":0,"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/posts\/384535\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/media\/384536"}],"wp:attachment":[{"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/media?parent=384535"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/categories?post=384535"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/shyamsteel.com\/wp-json\/wp\/v2\/tags?post=384535"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}