Building mortars are mixtures used for the jointing of bricks, stones, blocks etc.,
Mortar may be defined as a paste, capable of setting and hardening, obtained by adding water to a mixture of fine aggregates such as sand and binding material e.g., clay, gypsum, lime or cement or their combination.
Importance of Block Jointing Mortar in Present AAC Blocks era :
AAC blocks is a new kind of building materials which has heat preservation, thermal insulation, sound insulation, light weight, fire prevention and so on. It is a very ideal wall material simultaneously with high heat preservation and good surrounding protection function and is only one able to satisfy 65% energy savings index and has good developing prospects. However, AAC blocks is a silicate materials with very porous structure, the porosity reaches 70~80%. If the mortar usage and job practice are unsuitable, cracking and leaking in wall, hollowing and spalling in plastering layer and other quality defects are often rise, which affects seriously the application of AAC blocks.
For jointing those blocks the mortar should have excellent workability, good water retention high cohesiveness, small shrinkage. Mortar joint thickness is only 3~5mm and much smaller than that of traditional construction (level joint about 15mm, vertical joint about 20mm), not only saving raw materials but also facilitating the manage and construction. Furthermore, Block Jointing Mortar could reach a high wall-construction quality for its excellent workability, good water retention, higher cohesiveness and high crack resistance. It avoids piling up massive raw material in job location, reduces environment influence, especially in building face-lifting and improvement project in big or medium cities. Besides, the AAC blocks needn’t to sprinkle before building into wall, which can save water.
Which is cost-effective: AAC Block Jointing Mortar or traditional cement mortar for jointing AAC blocks?
Traditional sand cement mortar made at site can be used but it is advisable to use Thin-bed mortar designed especially for AAC block. It is delivered in ready-to-mix powder form. It is polymer modified Portland cement specifically designed to retain water from entering the pores of AAC blocks, which perfectly bond AAC blocks just 2–3mm thin mortar bed is needed to adhere the blocks. This is extremely thin joint which also prevents heat loss & speeds installation. Also reduction in dead weight leading to savings in steel & concrete.
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