what is cement in construction? Types of Cement . Properties of cement.

-


Q) what is cement in construction?


What is Cement?

A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. 

Types of Cement

Cement can be categorized into two main types – hydraulic and non-hydraulic cement. 

Hydraulic cement is formed by the reaction of powdered cement with water. You can use it for all types of construction, including underwater construction projects. Non-hydraulic cement sets and becomes adhesive due to carbonation. You can use it for various construction projects, except underwater construction projects. 

Hydraulic cement is the most commonly used cement. Portland cement is a type of hydraulic cement that’s been a preferred choice for architects, engineers, and constructors. The primary reason behind its popularity is its ability to harden quickly.  

Ordinary Portland cement (OPC)

When Portland cement clinker is mixed with gypsum, it forms OPC. OPC is further divided into three types, depending on their grade. The grade of cement is its compressive strength.

1)     Opc 33

2)     Opc 43

3)     Opc 53

Portland Pozzolana Cement (PPC)

Fly ash pozzolana or calcined clay pozzolana or a mixture of both is intimately ground with Portland clinker and gypsum (optional) to form PPC. PPC can be used in all types of construction, including marine and hydraulic construction.

Portland Slag Cement (PSC)

Granulated slag is ground with Portland cement clinker, gypsum and other additives to form PSC. Slag is the by-product of smelting ores. PSC is also suitable for all types of construction. However, it is mostly used in marine works. 

Properties of cement

·        Fineness:

It is the size of the particles of the cement. The desired fineness

 can be achieved by adjusting the grinding of the clinker.

·        Soundness:

Soundness is the ability of the cement to resist shrinking upon

 hardening. The Le-Chatelier test and Autoclave test help

 determine the soundness of cement.

·        Consistency:

Consistency of cement is the cement paste’s viscosity or its

 ability to flow. 

·        Strength:

The compressive, tensile and flexural strength of cement is

 measured to assess the durability of cement after an elongated

 period. 

·        Setting Time:

The setting time of cement is defined as the time required for

 the concrete to change from its liquid state to plastic state, and

 then from the plastic state to solid state. 

·        Heat of Hydration:

It is the energy generated when water comes in contact with

 cement. Heat of Hydration is a critical factor of curing

 concrete.



·        Loss of Ignition:

It is the process of measuring weight change of cement sample

 after it has been heated. Loss of ignition helps indicate

 adulteration of cement due to transportation or other factors.

·        Bulk Density:

Bulk density is the mass per unit of cement in a definite

 volume. 

·        Specific Gravity:

The specific gravity or relative density of cement is defined as

 the ratio of the mass of cement to the mass of the reference

 material which is usually water. 

 

 



Comments

Post a Comment

Popular posts from this blog

Advantage and disadvantage of RCC

-
  Advantage and disadvantage of RCC Advantage 1) Strength :- Rcc has very good strength in tension as well as compression. 2) Durability :- Rcc structures are durable if designed and laid properly. They can last upto 100 years. 3) Mouldability :- Rcc section can be given in any shape easily by properly designing the framework.  4) Ductility :- The steel reinforcement imparts ductility to the rcc structures. 5) economy :- Rcc is cheaper as compared to steel as prestressed concrete. 6) Transporation: - the raw materials which are required for rcc i.e. cement ,sand, aggregate, water, and steel are easily availableand can transported easily. Now a days Raidy mix concrete is used, 7) Fire resistance :- Rcc structures are more fire resistant than other commonly used construction materials like steel and wood. 8) Permeability :- Rcc is almost impermeable to moisture. 9) seismic resistance :- Properly designed Rcc structures are extremely resistant to earthquakes. Disadvantages 1) ...
Read more

1) Comparison of working stress method and limit state method

-
1)      Comparison of working stress method and limit state method. Working Stress Method  This method is based on the elastic theory which assumes that concrete and steel are elastic and the stress strain curve is linear for both. Limit State Method  This method is based on the actual stress strain curves of steel and concrete. For concrete the stress strain curve is nonlinear. Working Stress method In this method the factor of safety are applied to the yield stresses to get permissible stresses. Limit State Method In this method partial safety factors are applied to get design values. Working stress Method No factor of safety used for loads. Limit state method Design loads are obtained by multiplying partial safety factors of loads to the working loads. Working Stress method Exact margin of safety is not known. limit state method Exact margin of safety is known. Working stress method This method gives thicker so less economical. Limit state method This me...
Read more