The free moisture. content is that moisture which is on the surface of the aggregate . The value to be used for absorbed. moisture is found on the aggregate data sheets. (
How is free moisture content calculated?
Subtract the weight of the secondarily dried sample from the weight of the initial dried sample. Then divide this value by the weight of the secondarily dried sample. Then multiply this value by 100. If the resulting value is less than 0.1, the sample is considered sufficiently dry.
What is meant by moisture content?
Moisture content (MC) is a reference to the amount of moisture present in a material . This value is often represented as a percentage of the material’s mass (such as X% MC). The amount of moisture in an object can be measured in several different ways, such as with oven-dry tests or moisture meters.
What is free moisture and bound moisture?
17.1Free and bound water
Water that can be easily removed from foods is known as free water, whereas water that cannot be removed easily is termed as bound water.
What is the critical moisture content?
The critical moisture content is the average material moisture content at which the drying rate begins to decline . A prototype drying test should be conducted to determine the critical moisture content. ... The critical point (B) occurs when the superficial moisture has evaporated. In porous solids point B of Fig.
Is the moisture content?
Moisture content is, simply, how much water is in a product . It influences the physical properties of a substance, including weight, density, viscosity, conductivity, and others. It is generally determined by weight loss upon drying. There are many methods for determination of moisture content.
What is moisture content formula?
Calculate the moisture content on a wet-weight basis using the following formula: Moisture content (%) = W2 – W3 x 100 . W2-W1 . where, W1 = weight of container with lid; W2 = weight of container with lid and sample before drying; and W3 = weight of container with lid and sample after drying.
What is the purpose of moisture content?
Moisture content of the food material is important to consider the food is suitable before the consumption , because moisture content affects the physical, chemical aspects of food which relates with the freshness and stability for the storage of the food for a long period of time and the moisture content determine the ...
What is the importance of moisture content?
Moisture content has a lot to do with a food product’s characteristics , including its physical appearance (shape, color, etc.), texture, taste, weight (which can impact the cost) in addition to factors that affect the product’s shelf-life, freshness, quality, and resistance to bacterial contamination.
What are the types of moisture?
Generally, an aggregate has four different moisture conditions. They are Oven-dry (OD), Air-dry (AD), Saturated surface dry (SSD) and damp (or wet) .
Why is bound moisture difficult to remove?
Bound water.
Part of the moisture present in a wet solid may be adsorbed on surfaces of the solid or be absorbed within its structure to such an extent that it is prevented from developing its full vapour pressure and therefore from being easily removed by evaporation .
What is the difference between unbound and free moisture?
Here is the difference between bound and unbound water
Unbound is that water that is present on the surface . This water evaporates easily with a normal moisture balance . ... While bound water is that which is present in the capillaries . This water cannot evaporate freely and there is pressure on such type of water.
What is difference between drying and dehydration?
The key difference between drying and dehydration is that the drying refers to the removal of solvent from a solid, semi-solid or a liquid whereas dehydration refers to the removal of water from the water-containing compound. ... Moreover, these processes will leave a solid residue at the end.
What level of moisture is acceptable?
A range of 5 to 12 percent is considered optimal. A reading of up to 17 percent is generally considered moderate moisture and acceptable. Any reading over 17 percent is considered to be an indication of saturation and the need to replace the drywall and to take preventative measures against future moisture buildup.
What is equilibrium and critical moisture content?
The point which shifts to the Decreasing drying period from the Constant drying period is called the Critical moisture content Wc. The moisture content in which dryness does not advance any more is called the Equilibrium moisture content We.
What is equilibrated moisture?
n) “Equilibrated Moisture” means moisture content , as determined after equilibrating at 60% relative humidity (RH) and 40 degree Celsius as per the relevant provisions (relating to determination of equilibrated moisture at 60% RH and 40 degree Celsius) of BIS 1350 of 1959 or amendment thereof.
