Showing posts from May, 2017

Lightweight Aggregate Concrete: Types, Properties And Factors Affecting Mix Design

LWAC is the popular type of light weight concrete, in which lightweight aggregates are used. The lightweight aggregates are relatively new materials. These have a unit weight up to 12kN/m3. The LWA can be either natural or artificial or manufactured. The natural aggregates include volcanic cinder, dolomite or pumice. The artificial aggregates can be blast furnace slag, sintered fly ash or bloated clay.

Vacuum Concrete: Techniques, Equipments, Advantages and Disadvantages

One solution to the problem of converting a sufficiently high workability to a mix with a minimum desired water-cement ratio is attained by Vaccum- Dewatering of Freshly Placed Concrete. Concreting thin sections of slabs and walls will demand a mix of water cement ratio of 0.50 to 0.60. This is to facilitate proper placing and compaction. This mix will have less strength and abrasion resistance.
A treatment method that involves the removal of excess water and air by using suction is called as the vacuum treatment of concrete.

Dynamic Action on Buildings

The action of Wind and Earthquake will result in dynamic action on buildings. But the building design for wind and earthquake forces are different in nature.  Basic Concept in Wind Design of Structures
Mainly in the design based on a followed philosophy, force is considered as the basis for of structural design. This is more applied in the Wind design. Here, the idea is that the building surface is subjected to a force or pressure  (i.e. the wind force). This type is called as the force-type loading. The action is explained in the figure-1 below.

Fig.1. The Building Under Wind Force (Fw). It is maximum at the top story. Maximum displacement (Δ)is caused at the top of the building.

Basic Concept in Earthquake Design of Structures During an earthquake , the building is subjected to a random motion in the ground at the base of the structure. This will result in the formation of inertia forces in the building. This later gets converted into stresses. This type of loading is called the disp…


There exist minimum dimension of structural elements in civil engineering structures that have to be followed while designing and in implementation. It is irrespective of the codes and provisions. Minimum dimension is the value that has to be implemented how lower be the load conditions exist in that particular area.


Characteristic Compressive strength The compressive strength of the concrete is given in terms of characteristic compressive strength of 150mm sized cubes that is tested at 28 days ( fck). The characteristic compressive strength is defined as the strength of the concrete below which not more than 5% of the test results are expected to fall. The compressive strength of the cube samples although exhibit variations, when plotted on a histogram are found to follow the shape of a bell shape curve, as shown below.