STEP  1 

Objective:

To determine the static modulus of elasticity of hardened concrete in compression

Apparatus used:

Compression testing machine, extensometer or strain gauges

Specimen Type
Cylinder

STEP  2 

 Provide Specimen Details

Enter the Age of specimen:

Days

Select the Diameter(D) of the Specimen:

--Select-- 150 mm

Select the Length(L) of the Specimen:

--Select-- 300 mm

/

STEP  2  Preparation of cylinder specimens  Take out three cylinder specimens of size 300X150 from the curing tank.  Click on the cloth to wipe the surface of the samples to remove the excess moisture. / / /

STEP  3  a). Using a marker, central lines shall be drawn on the two opposite faces.
Note: Ensure that they are in the same axial plane.

STEP  2  Preparation of cylinder specimens  While in the wet condition, attach the extensometers (three equidistant from each other) in the
longitudinal direction, parallel to the axis and symmetrical about the centre of the specimen. / Gauge length /

STEP  3  Placement of specimen in CTM  Place the specimen with the attached extensometers in the testing machine centrally. / /

STEP  5  a). Click Numpad on CTM for zoom view. b). Apply the load continuously and without shock at a rate of 14 N/mm²/min until stress reaches F_c/9 (σb) and maintain stress F_c/9 for 60 s.

/

STEP  6   Specimen  a). Click on the dial of CTM for zoomed view. b). Click Start button of CTM to initiate the test. c). Apply the load continuously and without shock at a
Rate of 14 N/mm²/min until stress reaches F_c/9 (σb)
and maintain stress F_c/9 for 60 s. /

Time:		sec.

Click Next to Examine the fractured specimen.

STEP  4  Load Application:  Apply the load continuously and without shock at a Rate of 14 N/mm²/min until stress
reaches F_c/9 (σ_b) and maintain stress F_c/9 for 60 s.

STEP  8   Specimen  a). Steadily increase the stress at the constant
rate within the range 0.20 N/mm²/s to 0.30 N/mm²/s
until the stress equals F_c/3 (σ_a) and maintain for 60s. /

Time:		sec.

Click Next to Examine the fractured specimen

STEP  5  Load Application:  Steadily increase the stress at the constant rate within the range 0.20 N/mm²/s to 0.30 N/mm²/s
until the stress equals F_c/3 (σ_a) and maintain for 60s.

STEP  6  Specimen Centering  During the succeeding 30 s measure and record the strain readings taken at each measurement line. If the individual strains are not within a range of ±20 percent of their mean value at σ_a, recenter the test specimen and repeat the test. If it is not possible to reduce the differences to within this range do not proceed with test.

Gauge length Lo (mm)	Stress MPa	∆L (mm)			Longitudinal strain(𝛆)=∆L/Lo				Centering check (±20%)
		Line1	Line2	Line3	Line1	Line2	Line3	Average
100	11.55	0.032	0.036	0.046	0.00032	0.00036	0.00046	0.000380	Not ok

STEP 11  Specimen  a). Click on the specimen to recenter it. b). Click on the dial of CTM for zoomed view. c). Click Start button of CTM to initiate the test. c). Apply the load continuously and without shock at a
Rate of 14 N/mm²/min until stress reaches F_c/9 (σb)
and maintain stress F_c/9 for 60 s. /

Time:		sec.

Click Next to Examine the fractured specimen.

STEP 12  Specimen 

STEP 13  Specimen  a). Steadily increase the stress at the constant
rate within the range 0.20 N/mm²/s to 0.30 N/mm²/s
until the stress equals F_c/3 (σa) and maintain for 60s. b). Click Start button of CTM to initiate the test. c). Steadily increase the stress at the constant
rate within the range 0.20 N/mm²/s to 0.30 N/mm²/s
until the stress equals F_c/3 (σa) and maintain for 60s. /

Time:		sec.

Click Next to Examine the fractured specimen

STEP 14  Specimen 

STEP  6  Specimen Centering  After recentering

Gauge length Lo (mm)	Stress MPa	∆L (mm)			Longitudinal strain(𝛆)=∆L/Lo				Centering check (±20%)
		Line1	Line2	Line3	Line1	Line2	Line3	Average
100	11.55	0.033	0.035	0.034	0.00033	0.00035	0.00034	0.00034	Ok

STEP 16  Specimen  a). When the centering is sufficiently accurate, reduce the stress at the unloading rate same as loading rate to F_c/9 and maintain for 60s.

STEP  7  Preloading cycle  When the centering is sufficiently accurate, reduce the stress at the unloading rate same as loading rate to F_c/9 and maintain for 60s.

STEP 18  Specimen  a). Steadily increase the stress at the constant
rate within the range 0.20 N/mm²/s to 0.30 N/mm²/s
until the stress equals F_c/3 (σa) and maintain for 60s.

Time:

sec.

STEP  8  Preloading cycle  Repeat the preloading cycle for two additional loading cycles using the same loading and unloading rate, and maintaining the stress (σ_a and σ_b) constant for a period of 60 s.

STEP  9  Elasticity measurements  After completion of the last preloading cycle and a waiting period of 60 s under the stress σ_b = F_c/9 N/mm²,
the strain reading at the various measurement lines ε_b, during the succeeding 30s shall be recorded.

STEP  9  Elasticity measurements  After completion of the last preloading cycle and a waiting period of 60 s under the stress σ_b = F_c/9 N/mm²,
the strain reading at the various measurement lines ε_b, during the succeeding 30s shall be recorded.

Gauge length Lo (mm)	Stress MPa	∆L (mm)			Longitudinal strain(𝛆b)=∆L/Lo
		Line1	Line2	Line3	Line1	Line2	Line3	Average
100	3.85	0.011	0.012	0.012	0.00011	0.00012	0.00012	0.000117

STEP 10 Elasticity measurements  Increase the stress at the constant rate until the stress equals F_c/3 maintain for 60s. During the succeeding 30s, measure and record the strain readings a taken at each measurement line ε_a.

STEP 10 Elasticity measurements  Increase the stress at the constant rate until the stress equals F_c/3 maintain for 60s. During the succeeding 30s, measure and record the strain readings a taken at each measurement line ε_a.

Gauge length Lo (mm)	Stress MPa	∆L (mm)			Longitudinal strain(𝛆a)=∆L/Lo
		Line1	Line2	Line3	Line1	Line2	Line3	Average
100	11.55	0.034	0.036	0.035	0.00034	0.00036	0.00035	0.000350

STEP 24  Specimen  a). When all elasticity measurements have been completed, the load on
the test specimen shall be increased, at the specified rate, until failure of the specimen occurs. b). Click Start button of CTM to initiate the test. c). Steadily increase the stress at the constant
rate within the range 0.20 N/mm²/s to 0.30 N/mm²/s
until the stress equals F_c/3 (σa) and maintain for 60s.

STEP 11 Loading to failure  When all elasticity measurements have been completed, the load on the test specimen shall be
increased, at the specified rate, until failure of the specimen occurs.

STEP 11 Loading to failure  Check if stress at failure is within a range of ±20% of F_c. If not, this shall be noted in the test report and it shall be reported that the results may not be reliable.

MPa	Stress at failure (MPa)	Failure check(±20%)
34.65	37.12	Okay

STEP 12 Calculate the modulus of Elasticity  The mean strain ε_a and ε_b respectively shall be calculated and the static modulus of elasticity in compression is calculated.

sample	Stress, MPa	Stress, MPa	Strain, 𝛆a	Strain, 𝛆b	Static modulus of elasticity, (MPa)
1	11.55	3.85	0.000350	0.000117	33047
2
Average

STEP 13 Repeat the procedure on the second specimen and take the average.

sample	Stress, MPa	Stress, MPa	Strain, 𝛆a	Strain, 𝛆b	Static modulus of elasticity, (MPa)
1	11.55	3.85	0.000350	0.000117	33047
2	11.55	3.85	0.000337	0.000113	34375
Average					33711

Report

Size of cube specimen for compressive strength testing	150X150X150
Size of Cylindrical Specimen for modulus of elasticity Calculation	Diameter 150mm, Length 300mm
Concrete cube strength, MPa	43.31
Equivalent cylinder strength, MPa	34.65
Average Static modulus of elasticity, MPa	33711

STEP 11  Specimen 3  a). Click on the dial of CTM for zoomed view. b). Click Start button of CTM to initiate the test. c). Click Stop Button to see Values /

Load at Failure:		KN
Time:		sec.

Click Next to Examine the fractured specimen.

STEP 12  Specimen 3  Examine the fractured specimen.

 

 Fracture type

/ --Select-- Satisfactory Unsatisfactory

Click Next to Repeat the test.

STEP 11  Specimen 3  a). Click on the dial of CTM for zoomed view. b). Click Start button of CTM to initiate the test. c). Click Stop Button to see Values /

Load at Failure:		KN
Time:		sec.

Click Next to Examine the fractured specimen.

STEP 12  Specimen 3  Examine the fractured specimen.

 Fracture type

/ --Select-- Satisfactory Unsatisfactory

STEP 13 Observations: Click Show button to see load at failure of samples (P), failure type.

Specimen No.	Load at failure of samples (P)	Failure type
Specimen 1	kN
Specimen 2	kN
Specimen 3	kN
Specimen 3*	kN
Splitting tensile strength of samples (fct)
Specimen 1	MPa
Specimen 2	MPa
Specimen 3	MPa
Specimen 3*	MPa

STEP 16 Final Results: Click View button to see Results for new specimen

Splitting tensile strength (fct)
Specimen 1
Specimen 2
Specimen 3
Specimen 3*
Result: Average flexural strength =

Click Next to Generate Report.

STEP 17 Report Length (L) of specimen = Diameter (D) of specimen = Concrete grade=

No.	Identification mark	Age in days	Testing date	Maximum load(kN)	Failure type	Flexural strength(MPa)	Avg. value
1
2
3
4

STEP 17