Lake 12
Jahzara Lake
University of the Virgin Islands
ENG 201
1 March 2024
Concrete lab report
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Concrete stands as a foundation material for construction due to its versatility, durability, and
cost-effectiveness. Concrete is relatively strong and is utilized today for constructing buildings
and houses. It is composed primarily of Portland cement, aggregates (such as gravel and sand),
cement, and water, concrete undergoes a process called hydration, where water reacts chemically
with the cement to form a hardened matrix. This hydration process is crucial for the development
of concrete's strength and durability, as it forms the bonds that hold the aggregate particles
together. However, the exact composition of concrete, particularly the types and proportions of
its ingredients, can significantly influence its properties.
In this experiment, my group and I aim to investigate the impact of varying the composition of
concrete on its compressive strength. Specifically, we will be testing different mix designs by
altering the ratios of cement, water, and aggregates. By manipulating these variables, we
anticipate observing how changes in composition affect the hydration process and consequently
influence the strength of the resulting concrete cylinders.
Making forms: My group used dowel to create cylinder with the copy paper. Then we tape the
edges and bottom of the cylinder, so the concrete doesn’t slip out.
Composition of the cylinders:
Water
Cl
Control
Cement
1 part (40 mL)
Fine
Coarse/
aggregate
small ag
3 parts (120
4 parts (160
mL)
mL)
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C2
C3
Control
Control
1 part (40 mL)
4 parts (160
3 parts (120
mL)
mL)
2 parts (80
2 parts (80
2 parts (80
mL)
mL)
mL)
Materials needed:
Beach sand
Bowl
Portland cement
Spoon
Cylinder wooden stick
Paper
Tape
Fish tank Pebbles to replace aggregate
Step 1: Begin by placing the wooden cylinder onto a piece of paper and ensure it is securely
positioned. Roll the cylinder vertically to tighten it in place.
Step 2: Apply masking tape at three points along the length of the cylinder – towards the top,
middle, and bottom. Carefully slide the cylinder out and cover one of the holes with masking
tape. Repeat this process five more times to prepare a total of six cylinders.
Step 3: Divide the six cylinders into three sections, with two cylinders allocated per section.
Label each section accordingly for identification purposes.
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Step 4: Commence the mixing of the concrete mixtures.
Step 5: Measure out 40 ml of cement, 120 ml of beach sand, and 160 ml of pebbles into a mixing
bowl. Thoroughly mix these ingredients together, gradually adding water until the mixture
reaches a consistency that is neither too runny nor too clumpy.
Step 6: Fill two of the wooden cylinders with the first mixture, ensuring to compact it firmly for
better curing.
Step 7: Repeat the mixing and filling process with different measurements: 40 ml cement, 160 ml
beach sand, and 120 ml pebbles for one set, and 80 ml cement, 80 ml beach sand, and 80 ml
pebbles for another set.
Step 8: Place the filled cylinders into a tube holder for curing, allowing them to cure for both 2
weeks and 5 weeks.
Step 9: After the designated curing periods, proceed to break the cylinders.
Step 10: Before breaking the cylinders, record various measurements including the mass of the
tube and the ring, volume, height, diameter, and the distance between equipment.
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NOTE: Before my group and I began the process of breaking down the cylinders, we couldn't
help but notice that the consistency and appearance of the first three concrete samples seemed a
bit precarious, to say the least. It felt as though they were hanging on by a thread, requiring us to
handle them with the utmost care. We found ourselves delicately supporting them, almost as if
any sudden movement might cause them to disintegrate right before our eyes.
Step 11: Break the cylinders by incrementally applying weights onto the ring in 50-gram
increments until the tube fractures.
Step 12: Note the weight at which each tube breaks and calculate the corresponding force.
Step 13: Repeat the breaking process for the remaining cylinders at both the 2-week and 5-week
intervals.
NOTE: So, by the end of the 5-week curing period, we noticed some interesting variations
among the remaining three cylinders slated for testing. Interestingly, while the first three
cylinders felt precarious and seemed on the brink of fracturing even before applying any weights,
the last cylinder exhibited a significantly different behavior. It appeared noticeably sturdier and
seemed to withstand external forces much better than its counterparts. In fact, it took
considerably more effort and time to break this cylinder compared to the others.
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To break the cylinders, we used ring stands equipped with clamps positioned at specified
intervals. The clamps were set approximately 4 centimeters apart from each other, providing
ample support for the cylinders. Additionally, the rings stands were centered for each cylinder.
The pillow was centered right underneath the clamps, so if any weight falls off, it will stop it
from rolling down so nobody would get injured. The weight hanger was centered just like the
rings as well.
We added masses in increments of 50 grams, carefully placing each weight onto the weight
hanger. After each increment, we observed the response of the cylinder, monitoring for any signs
of structural stress or deformation. This incremental approach allowed us to systematically apply
force to the cylinders until they reached their breaking point, enabling us to accurately measure
their compressive strength. In terms of differences between the February 3 and February 24 tests,
there were not many significant changes in the procedure. However, we ensured consistency in
the setup and approach to maintain the reliability and comparability of the results between the
two test dates.
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Results (Data and Observations)
Class Data:
Group B: WEEK 2 of curing time
Cylinder #
Mass
length
B1
83.4 g
B2
74.3g
25.8cm
B3
101.5
26.8 cm
Diameter density
N/A
1.4 cm
g/cm3
1.3 cm
g/cm3
Total mass
at
breakage
N/A
1.87
210 g
2.87
760 kg
Notes
Too brittle; broke
immediately after
wrapping.
Group B: WEEK 6 of curing time
Cylinder #
Mass
B1
106.1g
B2
94.5 g
B3
length
Diameter
density
15.5cm
1.8 cm
N/A
14 cm
1.5 cm
N/A
101.5 g/ 26.8 cm
1.5 cm
2.22 g/cm3
Total
Notes
mass at
breakage
160 g
Cylinder with
the least
cement; broke
at first contact
310 g
Broke at first
contact
760 kg
Didn’t break at
first contact
compared to B1
& B2
GROUP F: WEEK 2 of curing time.
NOTE: This group only sent week 2 data and it wasn’t a 100% clear data, but I tried to fill in
what was sent to me.
Cylinder #
F1
Mass
101.3 g
length
23 cm
F2
112.8 g 27. 5m
Diameter
1.5/2 cm
Total mass at breakage
6710g
1 1/2
3410 g
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F3
99.g
26cm
1.5/2 cm
310kg
Group G: WEEK 2 of curing time
Cylinder #
G1
Mass
length
113.5g 24.9cm
Diameter
1.6 cm
density
27 g/cm3
Force
78.5 N
Total mass at breakage
8,000g
G2
117.9 g
25.5cm
2.037
78.5N
8,000g
G3
113.8g
26 cm
1.7cm
g/cm3
1.8 cm
g/cm3
1.72
39.3 N
4,000g
density
2.34g/cm3
WEEK 6 of curing time
Cylinder #
G1
Mass
122.3g
length
25.5cm
Diameter
1.6cm
Force
104.96N
Total mass at breakage
10.71g
G2
147g
25.2cm
2 cm
1.86g/cm3
98.1 N
10.01g
G3
83.8g
19.4cm
1.7 cm
1.9g/cm3
39.3N
4,000g
MY GROUP CYLINDERS
GROUP C
Week 2: Mass of the Ring=10 grams
Test
Mass
Volume
Height
Distance of E
Diameter
C1
88.4 grams
43cm
24.3cm
7cm
1.5 cm
C2
54 grams
23 cm
13cm
11cm
1.5cm
C3
98.5 grams
41.54 cm
27 cm
20 cm
1.4cm
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Breakeage
Force
C1
1010 grams
10241 N
C2
310 grams
3567.2 N
C3
210 grams
3023.0 N
Week 5/6
Mass of the Ring= 10 grams
Test
Mass
Volume
Height
Distance of E
Diameter
C1
96.1 grams
42.92cm
24.3cm
15cm
1.5 cm
C2
37.3 grams
17.66cm
10.0cm
9 cm
1.3cm
C3
120.5 grams
45.04 cm
25.5 cm
20 cm
1.5cm
Breakeage
Force
C1
5000 grams
5939.78 N
C2
2,500 grams
24963.54 N
C3
3,500 grams
35578.9N
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Discussions and conclusions
In the initial stage (early February), cylinders from Group B exhibited variations in
strength corresponding to differences in mixture ratios. Notably, cylinders B1 and B2, with lower
cement content, displayed brittle characteristics and broke upon minimal contact. Conversely,
cylinder B3, with a higher cement-to-aggregate ratio, demonstrated greater strength and
resilience.
Similarly, in Group F, although the data wasn’t clear, the recorded masses at breakage
suggest a connection between mixture ratios and strength. Cylinders with higher masses likely
had more great mixture ratios, contributing to their increased strength.
Comparing Group B's data from early February to early March, it's apparent that longer curing
time led to improvements in strength. In Week 6, cylinder B3, which had been curing for a
longer duration, showed enhanced strength and did not break in initial contact, unlike B1 and B2.
Group G's data further supports this trend. For instance, in Week 2, cylinders G1, G2, and G3
showed varying strengths, but by Week 6, there was a noticeable increase in strength across all
cylinders, indicating the positive impact of extended curing.
The overall class data emphasize the influence of mixture ratios and curing time on
cylinder strength. Cylinders from different groups showed varying strengths, primarily
attributable to differences in mixtures and curing duration.
This consistent observation across different groups implies that mixture ratios and longer curing
times generally lead to higher cylinder strengths.
In conclusion, the concrete lab data shows the significant impacts of mixture ratios and curing
time on cylinder strength. Cylinders with higher cement content and longer curing durations
tended to exhibit greater strength and resilience. These findings emphasize the importance of
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careful consideration of mixture design and curing practices in ensuring the quality and
durability of concrete structures.
References
Chemistry of cement. (n.d.). https://blackboard.uvi.edu/bbcswebdav/pid-989613-dt-content-rid27736381_1/courses/SCI301_SpringSemester2024_1_18615/ChemOfCement.html
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All about concrete – what you need to know. (2021, October 22).
https://www.thomasnet.com/articles/plant-facility-equipment/all-about-concrete-whatyou-need-to-know/
Michelle Peterson. Making concrete SCI 301. University of the Virgin Islands
Michelle Peterson. Breaking concrete. SCI 301. University of the Virgin Islands
Classmates. Class data. SCI 301. University of the Virgin Islands