Mortar strength relation among different days

Mortar is one of the most important materials of construction. It is a paste generally made by mixing cementing or binding (lime or cement) and inert materials (sand or surki) with water.

 The strength of mortar is tested by preparing a sample. In different days mortar shows different strength as it acquires its age or maturity.

The relationship among different days: We tested 72 mortar samples of different ages and different mixing ratios. Here we present the comparison,

Compare with 3 days,

             7 days strength = 40% more than 3 days strength

            14 days strength = 75% more than 3 days strength

            28 days strength = 95% more than 3 days strength

Compare with 7 days,

             14 days strength = 25% more than 7 days strength

             28 days strength = 40% more than 7 days strength

Compare with 14 days,

             28 days strength = 10% more than 14 days strength      

Methodology for Compressive Strength Test of Mortar

In order to conduct this study steps like data collection, analysis, laboratory test, development of strength-duration curve etc measures are measured. The whole procedure is divided into three stages:

• Pre-stage
• Working stage
• Observation and measurement stage

Pre-stage:

In this stage selection of materials is used. Here we used selection of fine aggregate and binding materials. As fine aggregate we selected Sylhet Sand and as binding materials we selected Shah Cement.

Working stage: In this stage following steps are followed:

• Mixing materials
• Preparing sample
• Curing and Testing

Mixing materials:

While mixing materials we used water-cement ratio (w/c) 0.485 as fixed for all samples. We used three verities of mix design as 1:2.5, 1:3 and 1:3.5.

Preparing sample:

For these purposes the compressive strength of 2”x2” mortar we used.

Curing and Testing:

Curing is the name given to procedure used for promoting the hydration of cement and consists of control of temperatures and of the moisture movement from and into the mortar. The object of curing is to keep mortar saturated so that hydration of cement can take place in a suitable environment. The curing for 28 days imparts maximum strength of mortar (Aziz, 1995).

Observation and measurement stage:

We took compressive strength in Mpa for 3 days, 7 days, 14 days and 28 days.