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Abrams' law (also called Abrams' water-cement ratio law) [1] is a concept in civil engineering. The law states the strength of a concrete mix is inversely related to the mass ratio of water to cement. [1] [2] As the water content increases, the strength of concrete decreases. Abrams’ law is a special case of a general rule formulated ...
Test methods for the water-cement ratio and fineness modulus). 1919 – Effect of Curing Condition on Wear and Strength of Concrete (Describing 120 tests on cylinder-shaped samples and 300 tests on cubic samples in various moisture conditions and testing periods varying from 3 days to 4 months).
Mortar holding weathered bricks. Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colours or patterns to masonry walls.
A lower ratio leads to higher strength and durability, but may make the mix more difficult to work with and form. Workability can be resolved with the use of plasticizers or super-plasticizers. A higher ratio gives a too fluid concrete mix resulting in a too porous hardened concrete of poor quality.
Their addition allows to decrease the water-to-cement ratio of concrete or mortar without negatively affecting the workability of the mixture. It enables the production of self-consolidating concrete and high-performance concrete. The water–cement ratio is the main factor determining the concrete strength and its durability. Superplasticizers ...
For both of these rules of thumb (85%/90% and major minus pitch), the tap drill size yielded is not necessarily the only possible one, but it is a good one for general use. The 85% and 90% rules works best in the range of 1 ⁄ 4 –1 in (6.4–25.4 mm), the sizes most important on many shop floors.
The lime mortar acts as a wick that helps to pull water from the brick. This can help to prevent the older brick from spalling. Even when the brick is a modern, harder element, repointing with a higher ratio lime mortar may help to reduce rising damp. It may not be advisable for all consumers to use a straight lime mortar.
The paste is generally mixed in a high-speed, shear-type mixer at a w/c (water to cement ratio) of 0.30 to 0.45 by mass. The cement paste premix may include admixtures such as accelerators or retarders, superplasticizers, pigments, or silica fume. The premixed paste is then blended with aggregates and any remaining batch water and final mixing ...