3 METHODS OF DETERMINING WORKABILITY OF CONCRETE

Different Test Methods for Workability Measurement Depending upon the water cement ratio in the concrete mix, the workability may be determined by the following three methods. Slump Test Compaction Factor Test Vee-bee Consistometer Test 1. Slump Test Suitability This method is suitable only for the concrete of high workability. This test is carried out with … Read more

FLEXURAL STRENGTH TEST OF CONCRETE (IS:516-2021)

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 (Part 1/Sec 1) : 2021 – Hardened Concrete – Methods of Test Part 1: Testing … Read more

HOW TO DETERMINE OF BOND STRENGTH BETWEEN STEEL & CONCRETE? [PULL OUT TEST]

APPARATUS FOR BOND STRENGTH TEST

Theory The bond strength is the measure of the effectiveness of the grip between concrete and steel and has no standard quantitative definition. In pull out tests on plain bars, the maximum load generally represents the bond strength that can be developed between concrete and steel. With plain bars the maximum load is not very … Read more

SLUMP TEST OF FRESH CONCRETE TO MEASURE WORKABILITY (IS-1199-1959)

Slump test of concrete to measure workability

Slump Cone Test of Fresh Concrete Object This test is performed to measure consistency or workability of fresh concrete, where the nominal maximum size of aggregate does not exceed 38 mm using slump test apparatus. Reference Standards IS : 1199 – 1959 – Method of sampling and analysis of concrete. Equipment & Apparatus Slump cone (Height … Read more

HOW TO DETERMINE DRYING SHRINKAGE OF HARDENED CONCRETE?

Length Comparator for measuring initial drying shrinkage of concrete specimen

Aim This test method describes the procedure for determining the drying shrinkage or change in length of concrete specimen due to changes in moisture content. Apparatus A length measuring apparatus incorporating a dial gauge capable of measuring the length accurately to 0.005 mm. (see fig shown below) Drying oven capable of maintaining a temperature of … Read more

WHAT IS NON-DESTRUCTIVE TESTING OF CONCRETE & VARIOUS NDT TEST METHODS?

NDT test on concrete

Non-Destructive Testing of Concrete (NDT on Concrete) Non destructive test is a method of testing existing concrete structures to assess the strength and durability of concrete structure. In the non destructive method of testing, without loading the specimen to failure (i.e. without destructing the concrete) we can measure strength of concrete. Now days this method … Read more

WHAT ARE THE MINERAL ADMIXTURES USED IN CONCRETE?

mineral admixuture-Metakoalin

The following 4 mineral admixtures can be used for making concrete. Rice husk ash Metakaolin Silica fume Fly as 1. Rice Husk Ash It is obtained by burning the rice husk in a controlled manner without causing environmental pollution. This is generated in huge quantity in the rice shelters and each tone of paddy produce … Read more

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

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