10 PRECAUTIONS TO BE TAKEN DURING PLACING OF CONCRETE

concrete placing precautions

Concrete Placing Precautions The concrete, as it comes out of the mixer or as it is ready for use on the platform, is to be transported and placed on the formwork. Following precautions should be taken during placing of concrete. The formwork or the surface which is to receive the fresh concrete should be properly … Read more

10 METHODS TO PREVENT PLASTIC SHRINKAGE CRACKING OF CONCRETE

Plastic Shrinkage Cracking of Concrete

Plastic shrinkage cracking (as shown below) is caused by rapid drying of the concrete surface. They can occur at any time of the year, from cooler low-humidity weather conditions to, in particular, hot weather conditions involving any one or a combination of high temperature, low humidity and wind. These types of cracks occur while the … Read more

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

Flexural Strength Test Arrangement

Objective To determine the Flexural Strength of Concrete, which comes into play when a road slab with inadequate sub-grade support is subjected to wheel loads and / or there are volume changes due to temperature / shrinking.  Reference Standards IS: 516-1959 – Methods of tests for strength of concrete Equipment & Apparatus Beam mould of size … Read more

7 STRUCTURAL EFFECTS OF SHRINKAGE ON CONCRETE STRUCTURES

shrinkage cracks in concrete

Effect of Shrinkage on Concrete Structure When concrete structures are not permanently water-saturated, it starts to lose moisture and starts to shrink from the time when the process of curing ceases. The structural effects of shrinkage area as follow. 1. Joints Shrinkage of concrete between movement joints causes joints to open or makes it wider. … Read more

WHAT ARE THE ADVANTAGES & DISADVANTAGES OF CONCRETE?

Effect of hot and cold weather on concrete

Advantages of Concrete The following are the advantages of concrete Concrete ingredients are easily available. Concrete can be easily handles and moulded to any desired shape. Concrete can be easily transported from the place of mixing to place of casting before initial set takes place. Concrete can be pumped or sprayed to fill into cracks … Read more

WHAT FACTORS INFLUENCE CORROSION OF REINFORCEMENT IN CONCRETE STRUCTURE?

factors influencing corrosion of reinforcement in concrete structure

Factors influencing Corrosion of Reinforcement In reinforced cement concrete construction the corrosion of reinforcement takes place due to the presence of chlorides and sulphates beyond a critical limit and when sufficient alkalies is not obtained within the concrete to maintain steel in a positive condition. The following factors are responsible for corrosion of steel reinforcement … Read more

WHAT ARE THE PROPERTIES OF FRESH CONCRETE?

Properties of Fresh Concrete

Properties of Fresh Concrete Concrete remains in its fresh state from the time it is mixed until it sets. During this time the concrete is handled, transported, placed and compacted. Properties of concrete in its fresh state are very important because the influence the quality of the hardened concrete. The fresh concrete has the following … Read more

WHAT IS RETEMPERING OF CONCRETE?

Retempering of concrete

Retempering of Concrete When water is added to a stiffened concrete or partially set fresh concrete in order to bring it back to the desired consistency or workability, then it is called “retempering of concrete’. Importance of Retempering of Concrete The one and only reason for retempering of concrete is to regain the lost workability … Read more

WHAT CAUSES CRACKS IN CONCRETE AND HOW TO PREVENT IT?

causes of cracks in concrete and its remedies

Causes of Cracks in Concrete and its Remedies Cracks in concrete are caused due to following factors. One of the main causes of cracks in concrete is the cooling and contraction due to setting of concrete. Volume change and stresses due to shrinkage are independent of any external load or stress applied. Cracks may develop … Read more