What is Admixture? It is an optional ingredient of concrete which is added to modify the properties of fresh and hard concrete and grout materials as per some specific requirements. Addition of admixture may alter workability, pumping qualities, strength development, appearance etc in fresh concrete and permeability, strength, durability etc in hardened concrete. But use … Read more
The followings are general recommendations or considerations for hot weather concreting. Guidelines to Follow 1. Do not exceed the maximum allowable water-cementious materials ratio or the manufacturer’s maximum recommended dosage of any admixture. 2. Consider retarding admixtures if their performance has been verified during trial batches. 3. Substitute ground, granulated blast furnace slag for part … Read more
During hot weather, problems that may occur in concrete include the following. Rapid slump loss Reduced air content Premature stiffening Plastic shrinkage cracks Thermal cracking Therefore it is necessary to keep concrete temperature down. The most effective way to keep concrete temperature down is by controlling the temperature of its ingredients. Among all ingredients of … Read more
Effects of hot weather on concrete, in the absence of special precautions can be as follows. Accelerated setting of concrete Reduction in strength of concrete Increased tendency to crack Rapid evaporation of water during curing period Difficulty in control of air in air-entrained concrete Accelerated Setting The rate of setting time of the concrete increases … Read more
Hand mixing is adopted for small works and where the quantity of concrete used is small. The following procedure is followed to mix concrete by hand. Procedure Construct a platform of bricks, lean concrete or iron sheets of a size as per requirement of the volume of concrete to be mixed. Spread out the measured … Read more
There are different methods of measuring the workability of fresh concrete. Each of them measures a particular aspect of it and there is no unique test which measures workability of concrete in its totality. The three most commonly used method for testing workability of concrete are Slump test Vee-bee test Compacting factor test. The table … Read more
In my previous post I discussed with you about volume batching of concrete and how it is done in field. Now let us solve an example, so that you become more confident in the field. In this example I have also tried o show you, how correction for bulking is applied and how correction of … Read more
What Is Volume Batching of Concrete? Batching of concrete means measuring different ingredients of concrete (i.e. cement, sand, coarse aggregate and water) before mixing it. When this measurement is done on the basis of volume, we call it Volume Batching. Below are mentioned some of important points to remember before adopting volume batching method in … Read more
Objective To determine the workability of freshly mixed concrete by using of Vee – Bee consistometer apparatus. Scope and Significance The workability of fresh concrete is a composite property, which includes the diverse requirements of stability, mobility, compactability, placeability and finishability. There are different methods for measuring the workability. Each of them measures only a … Read more
The following points should be remembered before proportioning a concrete mix a per IS-10262-2009. This method of concrete mix proportioning is applicable only for ordinary and standard concrete grades. The air content in concrete is considered as nil. The proportioning is carried out to achieve specified characteristic compressive strength at specified age, workability of fresh … Read more
Subscribe to our mailing list and never miss the latest blog post.
