My Blog

Author: haroonkhan

  • Silica

    —

    by

    haroonkhan
    in

    It contributes to the strength of cement due to the formation of dicalcium and tricalcium silicates. The excess presence of silica prolongs the setting time of cement but increases its strength.

  • Lime

    —

    by

    haroonkhan
    in

    It is the main constituent which contributes to the strength. Its proportion has to be properly maintained so as to make the cement sound and strong. Excess of lime makes the cement unsound and causes the cement to expand and disintegrate. On the other hand, if lime is deficient, the strength of the cement is…

  • INGREDIENTS OF CEMENT AND THEIR FUNCTIONS

    —

    by

    haroonkhan
    in

    The main ingredients in the manufacturing of cement are lime, silica, alumina and other oxides. The ingredients present in Ordinary Portland Cement are given in Table 6.1. The contributions by different ingredients are discussed below. Table 6.1 Ingredients of Portland cement

  • INTRODUCTION

    —

    by

    haroonkhan
    in

    Among the binding materials, cement is of recent origin compared to those used in the construction of different monuments throughout the world. Undoubtedly the credit goes to John Smeaton, a British Engineer, in the year 1756, who was given the responsibility of rebuilding the Eddystone lighthouse. Based on an exhaustive collection of information about the…

  • POZZOLANIC MATERIALS

    —

    by

    haroonkhan
    in

    Pozzolanic materials are siliceous and aluminous materials, which do not possess any cementitious properties but form cementitious compounds by reacting with lime in the presence of water. It is volcanic ash containing about 80% clay. The use of pozzolanic materials provides the following improvements: Naturally available pozzolanic materials are clay and shale, diatomaceous earth, volcanic…

  • Workability Test

    —

    by

    haroonkhan
    in

    An 1:3 lime mortar is made with adequate water. The mortar is thrown on a brick wall by a trovel. The sticking quality is examined. If it sticks well, then its workability is good.

  • Plasticity Test

    —

    by

    haroonkhan
    in

    A small quantity of lime is mixed with water and left overnight. The so-formed material is spread like butter on a blotting paper with a knife to test its plasticity. Good lime indicates high plasticity.

  • Impurity Test

    —

    by

    haroonkhan
    in

    A known weight of lime is mixed with water in a beaker and the solution is decanted. The residue is dried in the sun for 8 hours, cooled and weighed. Based on the percentage of residue, the quality of lime is decided. Residue of less than 10% indicates that the lime is good, 10–20% indicates…

  • Ball Test

    —

    by

    haroonkhan
    in

    Sufficient water is added to lime and a ball of the size of an egg is made. It is stored for 6 hours and then placed in a basin of water. If it shows expansion and disintegration in a few minutes, it signifies Class C lime. If the expansion is less with a number of…

  • Hydrochloric Acid Test

    —

    by

    haroonkhan
    in

    Hydrochloric acid of 50% strength is added to powdered lime kept in a test tube till effervescence ceases. Generally, a teaspoonful of powdered lime of about 10 cc is required. It is kept for 24 hours. The bubbling reaction indicates the presence of lime. The volume of insoluble residue signifies unwanted inert material. Class A…