WHAT ARE THE FACTORS INFLUENCING COMPRESSIVE STRENGTH TEST RESULTS OF CONCRETE?

Correction factor for height-diameter ratio of a core

Factors Affecting Strength Test Results of Concrete Compressive strength is the most important property of concrete. The compressive strength of concrete is determined in the laboratory in controlled conditions. On the basis of this test result we judge the quality of concrete. But sometimes the strength test results vary so widely that it becomes difficult … Read more

HOW TO CAP CONCRETE CYLINDERS? (4 METHODS OF CAPPING)

Capping mould with fix bar

Capping of Concrete Cylinders Capping is required to give a smooth surface for applying compressive load to concrete cylinders. Only cylindrical concrete test specimens are capped using appropriate method. When the ends of cylindrical test specimens are not plane within 0.05 mm, it is required to cap those test specimens. The capped surfaces should be … Read more

WHAT ARE THE ADVANTAGES OF PPC (PORTLAND POZZOLANA CEMENT)

Advantages of PPC (Portland Pozzolana Cement)

Advantages of PPC in Fresh Concrete Portland pozzolana cement (PPC) has following advantages when concrete is in its fresh state. 1. Workability Portland pozzolana cement has spherical cement particles and they have higher fineness value. Due to the spherical shape concrete move more freely and more fineness of particles allows better filling of the pores. … Read more

HOW TO FIND VOLUME OF CONCRETE PER BATCH?

volume of concrete per batch

Aim To determine volume of concrete per batch, where nominal maximum size of aggregate does not exceed 38 mm. Apparatus Balance – Sensitive to 0.01 kg Tamping bar – Length 38 cm, Weight 1.8 kg Cylindrical mould – Dia = 250 mm, Height = 280 mm, Capacity = 0.01m3 Step by Step Procedure to Calculate … Read more

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF CONCRETE FLOORING?

advantages and disadvantages of concrete flooring

Concrete flooring is a common type of flooring adopted by many building owners. Concrete flooring can be used in residential, commercial, institutional & public buildings of all types. Before choosing concrete flooring as an option for your building construction, you should know the advantages and disadvantages of it. Advantages of Concrete Flooring 1. Durability A … Read more

HOW TO INSPECT PHYSICAL CHARACTERISTICS OF AGGREGATE USED IN CONCRETE?

While inspecting aggregate for quality control purpose, it is required to describe its physical properties, because physical properties of aggregate have an effect on the property of concrete. The physical properties of aggregate which should be described are given below. Name of parent rock & Group name Particle Shape Surface Texture Let us see how … Read more

HOW TO BLEND AGGREGATE USING FINENESS MODULUS VALUE?

Sometime it may happen that, the aggregate available at site is not conforming to the desired grading. In such case two or more aggregates from different sources may be combined to get the required grading. Fineness modulus value can be used as a technical way to blend coarse aggregate with fine aggregate to produce desired … Read more

HOW TO DO SAMPLING OF FRESH CONCRETE IN THE FIELD?

How to do sampling of fresh concrete

Sampling of Fresh Concrete To ensure it is representative of the whole truck load, a standard sample consists of scoopfuls taken from different parts of the batch and collected in bucket. Scoopfuls must be taken through the moving stream, as the load is discharged, sampling the whole width and depth (not just the top part). … Read more

WHAT ARE THE EFFECTS OF HOT & COLD WEATHER ON CONCRETE?

Effects of Hot Weather on Concrete Any operation of concreting done at atmospheric temperature above  400C may be put under hot weather concreting. The effect of hot weather may be as follows: Accelerated setting: A higher temperature of fresh concrete results in a more rapid hydration and leads to reduced workability/ accelerated setting. This reduces … Read more

HOW TO TEST AGGREGATE FOR BULK DENSITY AND VOIDS?

Objective Determination of unit weight or bulk density and void of aggregates. Equipments Name Capacity 1. Balance Sensitive to 0.5% of weight of material 2. Cylindrical metal measure Of 3 litre capacity (for fine aggregate) Of 15 litre capacity (for aggregate upto 40mm) 3. Tamping rod 16 mm dia. and 60 cm long Sample Preparation … Read more