HOW TO MAKE TEST CUBES FROM FRESH CONCRETE?

Self compacting concrete

Making of Test Cubes From Fresh Concrete IS-456 has laid down the acceptance criteria of quality concrete. In all the cases, the 28-days compressive strength shall alone be the criterion for acceptance or rejection of the concrete. 7 days compressive strength of concrete can be carried out in order to get a relatively quicker idea … 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 FIND VOLUME OF CONCRETE PRODUCED PER BAG OF CEMENT?

volume of concrete produced per bag of cement

Aim To determine volume of concrete per bag of cement, 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 Procedure Step-1 (Measuring Volume … 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

SLUMP & COMPACTION FATOR – WHAT IS THE RELATION BETWEEN THEM?

How to manage slump loss in concrete

Generally we specify workability of concrete in terms of its slump test value. But sometimes it is also specified by another test called compaction factor. The relation between slump and compaction factor is roughly as follows. Relation Between Slump & Compaction factor Workability Slump in mm Compaction factor Very stiff – 0.70 Stiff 0 to … Read more

FLOW TABLE TEST TO MEASURE FLOW VALUE OF CONCRETE

Objective To measure flow value of concrete using flow table apparatus Equipment Flow table Slump cone shaped mould Wooden tamping bar   Procedure Place the flow table on a leveled surface Clean the top of the table and inner surface of the mould using a damp cloth. Place the slump cone centrally on the table. … Read more

WHAT ARE THE ADVANTAGES AND LIMITATIONS OF SLUMP TEST?

Advantages of Slump Test It grants the facility to easily detect the difference in water content of successive batches of concrete of the same identical mix. The apparatus is cheap, portable and convenient to be used at site. Limitation of Slump Test As such, there is no direct relationship between the workability and the value … Read more

WHY DETERMINATION OF SETTING TIME OF CONCRETE IS IMPORTANT?

Determination of setting time of concrete helps a site engineer in guiding the following areas. Importance of Setting Time of Concrete Whether or not to use any plasticizer To find out effectiveness of set controlling admixture Regulating maximum time of mixing transit, placing and compacting Whether or not to provide protection against adverse weather condition … Read more

WHAT ARE THE FACTORS RESPONSIBLE FOR SETTING TIME OF CONCRETE?

The setting time of concrete depends upon following factors, such as Water-cement ratio Temperature condition Type of cement used Use of mineral admixture Use of chemical admixture (such as plasticizer) Other factors which may affect the setting time of concrete includes Absorption of mixing water by aggregates Grinding of aggregates in the mixer Of all … Read more

WHAT IS SETTING TIME OF CONCRETE?

Penetration Resistance Apparatus

The various process involved in any concreting operation involves the following stages. Mixing Transporting Placing Consolidating As concrete passes from one stage to another, it starts to lose its plasticity characteristics. If after placing it is not disturbed for a longer time period, then it starts to become stiffening. As a result concrete changes its … Read more