LIME & MORTAR is a mixture of sand, silt, soil, water. it is used in building material, in artical we study about Composite Mortar or Gauge Mortar, Workability, Building limes, Benefits of cement-lime mortar, Lime And Mortar | Planner Stickers
- Mortar is a homogeneous mixture, produced by intimately mixing cementitious materials, water, and inert materials, such as sand, to the required consistency for use in building together with masonry unit. The water-cement ratio is more in the mortar than concrete.
- Lime Mortar – A mortar containing lime and sand.
- Composite Mortar or Gauge Mortar – A mortar containing cement and lime in addition to other ingredients.
- Water Retentivity – The ability of mortars to retain water against suction and evaporation in general. It is indirectly a measure of the workability of mortars. It is measured by the flow of mortar when tested on a standard flow table before and after the application of a specified suction.
- Workability – That property of freshly mixed mortar which determines the ease and homogeneity with which it can be mixed, placed, compacted, and finished. It is the amount of energy to overcome friction and cause full consolidation.
- Sand for mixing mortar should be well graded.
- Lime is not essential for H1 and H2 for consideration of strength but its addition improves workability.
- But adding hydrated lime to the mortar mix can be beneficial. The plasticity or workability of the mix is better. When hydrated lime is added to the mix, the sand and the cement do not separate. The final mortar also is more waterproof. Shrinkage cracking often can be eliminated or minimized when hydrated lime is used.
- Lime provides high water retention that allows for maximum early curing of the cementitious materials.
- High initial flow which permits easy complete coverage of masonry units
- The low air content of cement-lime mortar increases bond strength.
- Hydrated lime improves the strength of the mortar by carbonation, Hydrated lime reacts with carbon dioxide in the atmosphere to form limestone.
- The addition of lime also makes masonry waterproof.
Building limes shall be classified as follows:
- Class A – Eminently hydraulic lime used for structural purposes. (Clay content is 25%)
- Class B – Semi-hydraulic lime used for masonry mortars, lime concrete, and plaster undercoat. (Clay content is 15%)
- Class C – Fat lime used for finishing coat in plastering, whitewashing, composite mortars, etc, and with the addition of pozzolanic materials for masonry mortar. (Clay content is 7.5 %)
- Class D – Magnesium/dolomitic lime used for finishing coat in plastering, whitewashing, etc.
- Class E – Kankar lime used for masonry mortars.
- Class F – Siliceous dolomitic lime used for undercoat and finishing coat of plaster.
- Lime Stone is a Sedimentary Rock with a High Percentage of CaCo3 (Calcium Carbonate)
- When CaCo3 is heated at 10000C in Rotatory Kiln, CO2 is liberated and Quick Lime (CaO, calcium oxide is formed)
- Addition of Quick lime and Water gives Exothermic reaction and Ca(OH)2 Calcium hydroxide is formed this process is know as slacking of lime.
- POPPING AND PITTING TEST OF LIME to study the unsoundness of building limes
- LIME REACTIVITY TEST This method of test covers the procedure for determining the reactivity of the pozzolanic material (such as fly ash) with hydrated lime, as represented by compressive strength of standard mortar test cubes prepared and tested under specific conditions. Using 50mm mold cure at 90 to 100% relative humidity at 500C + 20C for a period of eight days. Samples shall not be cured underwater.
- TEST TO CHECK TOTAL CALCIUM OXIDE IN LIME The lime should have a purity of at least 70% by weight of CaO when tested
- COMPRESSIVE STRENGTH OF BUILDING LIME Using 50mm mold and test after 7,14,21,28 days
- BALL TEST This test is used to differentiate the Class A, B, C, lime. A ball of egg size is made and stored for 6 hours, if ball expands or disintegrates in a few minutes then it is Class-C, little expansion with numerous cracks it is Class-B and NO adverse effect it indicates Class-A.
- Rest all tests are the same as done with cement.
LIME And MORTAR
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