HOW TO PREVENT BLEEDING AND LAITANCE IN CONCRETE?

Preventing Bleeding

Bleeding cannot be completely prevented as it is an inherent property of concrete. But it can be minimized if following precautions are taken. By proper proportioning of concrete mix. By mixing the concrete uniformly and completely. By using finely divided pozzolanic materials ( as it creates a longer path for the water to traverse and … Read more

HOW TO AVOID SEGREGATION OF CONCRETE?

Avoiding Segregation in Concrete

The danger caused by segregation is difficult to repair and very costly. Therefore necessary precautions should be taken to avoid segregation. Precautions to Take The concrete mix should be properly designed with optimum quantity of water to make a cohesive mix. Such concrete will not exhibit any tendency for segregation. Field quality control must be … Read more

DETERMINATION OF FIELD DENSITY OF SOIL BY SAND REPLACEMENT METHOD (IS-2720-PART-28)

Sand Replacement Method

Aim To determine the field density of soil at a given location by sand replacement method Reference IS-2720-Part-28-Determination of dry density of soils in place, by the sand replacement method Apparatus Sand pouring cylinder Calibrating can Metal tray with a central hole Dry sand (passing through 600 micron sieve) Balance Moisture content bins Glass plate … Read more

DETERMINATION OF FIELD DENSITY OF SOIL BY CORE CUTTER METHOD (IS-27270-PART-29)

Core cutter, Dolly & Rammer

Aim To determine the field density of soil by core cutter method Reference IS-2720-Part-29-Determination of dry density of soil in place by the core-cutter method Apparatus Cylindrical core cutter Steel rammer Steel dolly Balance Steel rule Spade or pickaxe Straight edge Knife Procedure Measure the height (h) and internal diameter (d) of the core cutter … Read more

5 EASY STEPS TO CHOOSE MOST APPROPRIATE TYPE OF FOUNDATION

Different type of foundations

There are three principle factors to consider before choosing the most appropriate type of foundation for a given structure. These are as follow Function of the structure and loads it must carry The sub surface condition Cost of foundation in comparison with cost of the superstructure Because of these factors, there exist several acceptable solutions … Read more

4 PHASES INVOLVED IN BORED CAST IN-SITU PILE CONSTRUCTION WORK

Pile installation process

Piles can either be driven into the ground (driven piles) or be installed in a predrilled hole (bored piles or drilled shafts). The construction of bore cast in situ concrete pile consists of 4 primary phases 1.Pile boring, 2.Reinforcement cage lowering, 3.Flushing 4.Pile concreting. Now we will discuss each phase one by one. 1. Pile … Read more

BULKING OF FINE AGGREGATE – WHAT, WHY & HOW?

percentage of bulking of sand with moisture content

The volume increase of fine aggregate due to presence of moisture content is known as bulking. Fine sand bulks more as compared to coarse sand. Extremely fine sand particularly the manufactured fine aggregate bulks as much as about 40%. Note: Fine aggregate do not show any bulking when it is absolutely dry or completely saturated. … Read more

CORRECTION APPLIED TO SPT VALUE

The N-value observed during testing is not utilized directly in assessing soil properties. These values are corrected to account for The overburden pressure Dilatancy in saturated fine sands and silts Correction for overburden pressure The penetration resistance of soil depends on the over burden pressure. At deeper depth in-situ soil will have higher overburden pressure … Read more

COMPRESSIVE STRENGTH TEST OF CONCRETE (IS:516-1959)

Compressive Strength Test on Concrete

Objective The tests are required to determine the strength of concrete and therefore its suitability for the job.  Reference Standards IS : 516-1959 – Methods of tests for strength of concrete. Equipment & Apparatus Compression testing machine (2000 KN) Curing tank/Accelerated curing tank Balance (0-10 Kg)   Procedure  Representative samples of concrete shall be taken and … Read more

AGGREGATE FLAKINESS INDEX VALUE (IS:2386-Part 1-1963)

Thickness Gauge

Objective For determination of flakiness index of coarse aggregate, where the  size of the coarse aggregate are larger than 6.3mm .  Reference Standards IS : 2386 (Part I) – 1963 – Method of test for aggregates for concrete (Part I) Particle size and shape. Equipment & Apparatus Thickness gauge Sieves [63, 50, 40, 31.5, 25, … Read more