Factors Affecting the Setting and Hardening of Portland cement (1) The Impact of Cement’s Composition The mineral composition of cement and their ratios are the main factors affecting the setting and hardening of cement. As mentioned above, various mineral components will reveal different characteristics when reacting with water. For example, the increase of C3A can … Read more
Flow Table Test for Cement Mortar The flow table test of cement mortar is done only to calculate the amount of water required for gauging for conducting strength test of masonry cement and for drying shrinkage test of cement. It also gives us some idea on the workability of cement mortar. The amount of water … Read more
Types of Soil Shear Test Based on Drainage Condition The shear strength parameters in the case of saturated soils depend very much upon the drainage conditions and therefore in the laboratory shear test, the drainage condition expected in the field for a particular problem should be simulated. Based on drainage condition the shear tests are … Read more
Popping and Pitting Test of Lime Objective To determine popping and pitting of lime sample as per IS-6932-part-10 Theory This test is a measure to study the unsoundness of building limes. Popping, pitting and blowing are due to the presence of coarse unslaked or only partially slaked particles. On final slaking, these cause dislodgement of … Read more
Defects in Brickwork The followings are some of the common defects in brickwork that are found at construction site. The bricks used were of substandard quality compared to the quality specified in the contract. No tests were carried out to find out the efflorescence level and water absorption in the bricks The bricks were not … Read more
Quality Requirements of Pumped Concrete Pumped concrete can be used for most structural concrete construction but is most useful where space for construction equipment is limited or access is difficult. Concrete pumps can be either truck- or trailer mounted and range from small units, exerting pressures from 250 to 300 psi and outputs of 15 … Read more
Characteristics of Good Mortar The chief properties of hardened mortar are strength, development of good bond with building units, resistance to weathering and those of green mortar mixes are mobility, placability and water retention. In addition, the mortar should be cheap and durable and should not affect the durability of building units in contact. The … Read more
Processing of Borrow Area Soils / Backfill Materials The construction of subsurface structures often requires the construction of elements of the structure within or upon large masses of backfill. The proper functioning of these elements are often critically affected by adverse behavioral characteristics of the backfill. Behavioral characteristics are related to material type, water content … Read more
What is Corrosion of Steel? The term corrosion is defined as an act or process of gradual wearing away of a metal due to chemical or electro-chemical reaction by its surroundings such that the metal is converted into an oxide, salt or some other compound. A substance known as rust results from such a process. … Read more
Impurities in Sand Clay, silt, salts, mica and organic matter are a source of impurities in sand. All sands are generally found to contain some percentage of silt and clay. Mica is easily discernible from its shining surface. A certain percentage of impurities are inevitable in sand; a maximum of 6 % of silt and … Read more