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Qualities of Sand and Water for Mortar
Qualities of Sand and Water for Mortar: Cementing materials (for example, cement) cannot be used directly as a building material without coupled with an inert substance such as aggregates. Thus, mortar is a composite material made by closely mixing a binding substance (cement or lime) with a fine aggregate (sand) in a predetermined proportion and with an acceptable amount of water. Here, lime or cement facilitates the formation of a good connection between the particles, while sand gives mechanical strength to the mortar.
When preparing a mortar for use in construction works, we need to make sure that the cement and sand use for mortar preparation are of good quality. This helps to ensure the soundness of the hardened mortar and to eliminate any issue that can be raised from bad quality ingredients.
Qualities of Sand for Mortar
Sand particles are silica-rich small soil grains. Sand is often defined as particles with a diameter higher than 0.075 mm but less than 4.75 mm.
Sand is a naturally occurring material that may be categorized into three types: (i) pit sand, (ii) river sand, and (iii) sea sand. Sea sand is unsuitable for using in mortar.
Sand is divided into three types for mortar purposes: fine, coarse, and gravelly sand. Fine sand passes through a screen with 1.59 mm clear openings, coarse sand goes through a screen with 3.18 mm clear openings, and gravelly sand travels through a screen with 7.62 mm clear openings. Plastering requires fine sand, whereas masonry requires coarse sand.
The following qualities of sand are necessary for mortar:
- It should be completely devoid of organic stuff.
- Chemically, it should be inert.
- It should be appropriately graded.
- Sand should have a fineness modulus of between 2 and 3.
- It should be sharp, angular, coarse, and clean in appearance.
Qualities of Water for Mortar
Water is utilized in Civil Engineering projects for a variety of purposes, including the development of earth structures, road construction, concrete work, and so on. Although water is a critical component of building materials, it is often overlooked, especially in the building of earth buildings and highways.
However, proper attention is paid to the preparation of mortar and concrete. The widespread notion is that if a substance is acceptable for drinking, it is also appropriate for building purposes, including mortar and concrete. The quality of water used in the manufacture of mortar and concrete, as well as for curing, is explored in more detail.
Because water contributes to the formation of cement gel, which is a critical aspect in determining the strength of mortar or concrete, the amount and quality of water must be carefully chosen.
The quality of mixing water may be assessed in one of many ways:
- If the water comes from an unknown source, the strength of the mortar or concrete built with it is compared to that created with pure water.
- If the pH value of water is between 6 and 8, it is considered to be organic matter-free and hence acceptable.
The inclusion of the following contaminants may have an adverse effect on the mortar if an excessive amount is permitted:
- Suspended particle content of less than 0.02 percent
- Presence of salts: chlorides not exceeding 10,000 parts per million; sulphates not exceeding 3,000 parts per million
- Acids and alkalis present: detrimental
- Algae presence: detrimental