laitance


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laitance

[′lat·əns]
(materials)
Weak material, consisting principally of lime, that is formed on the surface of concrete, especially when excess water is mixed with the cement.

laitance

The accumulation of fine particles on the surface of fresh concrete resulting from an upward movement of water in the concrete; occurs when excessive water is used in the mixing of the concrete.
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References in periodicals archive ?
Laitance still forms at the surface of this type of material, so it must be removed with any curing compounds prior to coating application.
Preparation involves cleaning of mold release agents, laitance, efflorescence, and other contaminants.
This removed any dirt, oil, grease, loose mortar, concrete, aggregates, laitance or other contaminants.
Cleaning rates of up to 20 square metres of paint, rust or concrete laitance per hour are possible and in recent side-by-side trials, the Blastrac 1-7D cleaned an area three times as quickly as its competitors, in just one pass.
Dusting occurs when a small, thin weak layer called "laitance" appears.
Thus, the high percentage of grout weakens the effect on interlocking and framework structure, which even results in segregation, laitance, and bleeding during the vibrating.
Laitance is a loose or powder layer of material on top of concrete.
This removes the paint, rust or concrete laitance, which is then drawn away with any dust to a filter plant or industrial vacuum cleaner.
In the footing, deep pockets of laitance and large voids extended beneath the pier along this face.
Tenders are invited for Prestressed CFRP laminates lOOnim x 1.4 mm-Supplying, providing and fixing of procured carbon fibre laminates of size 100 mm wide and 1.4 mm thick with compatible structural adhesive including surface preparation ( grinding of concrete substrate, cleaning it with wire brush, removing oil, laitance if present), profiling in parabolic manner or as per design requirement (applying compatible printer on prepared substrate.
Direct tensile and shear tests performed on specimens of concrete cast upon HPFRCC IPC laminates show that failure never occurs in the interface between both materials, but either in the laitance layer of the concrete or interlaminar between the glass fibremat layers in the HPFRCCIPC.