CIVE1265 Concrete lab Part 1

Summary

The video script details a civil engineering lab session at Bandura East Campus, focusing on concrete casting. The process involves calculating ingredient quantities for 30 MPa concrete, measuring materials using a scale, and mixing in a concrete mixer. It demonstrates mixing dry materials first, then adding cement and water. The script also covers conducting a slump test, filling molds, and vibrating to remove air bubbles. Finally, it mentions the curing process, involving water curing for seven days before testing.

Takeaways

• 🏛️ The video is set in the Bandura East Campus, specifically focusing on the civil engineering facilities.
• 🔬 The objective is to prepare and cast 30 MPa concrete, requiring precise measurement of cement, water, sand, and aggregates.
• 📏 The script outlines the need to calculate the total volume and the required quantities of each ingredient based on a mix design.
• 📐 The calculated quantities are: cement at 5.91 kg, water at 1.9 kg, sand at 8.84 kg, and aggregate at 20.21 kg.
• ⚖️ A scale is used to measure the exact amounts of each ingredient, ensuring accuracy in the concrete mix.
• 🏗️ The smallest concrete mixer, with a 60-liter capacity, is used for mixing the concrete ingredients.
• 🔄 The mixing process involves first combining the dry materials, then adding cement, and finally, water.
• 📏 The script describes a slump test to measure the consistency of the concrete, which yields a reading of 180 millimeters.
• 🗜️ The concrete is then poured into molds, vibrated to remove air bubbles, and leveled off for uniformity.
• 🕒 After molding, the concrete specimens are left to cure for 24 hours before being demolded and placed in water curing tanks for seven days.
• 🔍 The final step involves testing the cured concrete samples, showcasing the importance of the curing process for strength and quality.

Q & A

Where is the speaker located at the beginning of the transcript?

The speaker is located in the Bandura East Campus, specifically outside building 25253.

What type of concrete is being cast according to the transcript?

The type of concrete being cast is 30 MPa concrete.

What are the four main ingredients required for the concrete mix as mentioned in the transcript?

The four main ingredients required for the concrete mix are cement, water, sand, and aggregates.

How many specimens are being prepared according to the transcript?

Five specimens are being prepared, with an additional 25% added to the total volume.

What is the required quantity of cement for the concrete mix as per the calculations in the transcript?

The required quantity of cement for the concrete mix is 5.91 kilograms.

What is the quantity of water needed for the concrete mix as mentioned in the transcript?

The quantity of water needed for the concrete mix is 1.9 kilograms.

What is the role of the 10 millimeter cross aggregate in the concrete mix?

The 10 millimeter cross aggregate is used as part of the coarse aggregate in the concrete mix.

What is the procedure for mixing the concrete as described in the transcript?

The procedure involves first mixing all the dry materials, then adding cement to the fine and coarse aggregate, and finally adding water.

What is the slump test mentioned in the transcript, and what is the recorded reading?

The slump test is a test to measure the consistency of the concrete. The recorded reading is around 180 millimeters.

How long do the specimens need to be cured in the water tank before being tested?

The specimens need to be cured in the water tank for seven days before being tested.

What is the purpose of the curing tanks mentioned in the transcript?

The purpose of the curing tanks is to soak the specimens in water for the curing process, which is essential for the concrete to gain strength.

Outlines

00:00

🏗️ Concrete Mixing and Measuring Ingredients

The speaker is at the Bandura East Campus, specifically in front of Building 25253 where civil engineering is located. They discuss the process of preparing 30 MPa concrete, detailing the required ingredients: cement, water, sand, and aggregates. The quantities needed are calculated according to the lab manual, with specific amounts given for cement (5.91 kg), water (1.9 kg), sand (8.84 kg), and aggregates (20.21 kg). The ingredients are measured using a scale, and the process of mixing them in a concrete mixer is described, starting with the dry materials and ending with the addition of water.

05:09

📏 Slump Test and Mold Filling

This paragraph describes the process of performing a slump test on the concrete mixture. The speaker explains how to stack the concrete into a cone shape, tamp it 25 times, and then fill the next one-third layer, repeating the process until the cone is full. After lifting the pole, a roller is used to measure the slump, which in this case is around 180 millimeters. The paragraph then transitions into the process of filling molds with the concrete, emphasizing the importance of vibrating the mold to remove air bubbles and achieve a uniform surface.

10:16

🛠️ Curing Process and Specimen Preparation

The focus of this paragraph is on the curing process of the concrete specimens. After the concrete is poured into molds and vibrated to remove air bubbles, the speaker explains that the specimens need to be left for 24 hours before demolding. The next day, the specimens are to be placed in curing tanks for water curing, where they will be soaked for seven days before testing. The curing tanks are described as containing water to keep the specimens moist, and the speaker mentions that previously demolded samples can be seen in the tanks.

15:18

🔄 Demolding and Curing Tank Setup

The final paragraph discusses the demolding of the concrete specimens, which is to be done the following morning. The specimens are then to be brought to the curing tanks for the week-long curing process before testing. The speaker provides a view of the curing tanks and mentions that they contain previously demolded concrete samples, indicating that the process is a standard part of the concrete testing workflow.

Keywords

💡Bandura Campus

Bandura Campus refers to a specific location where the video is set. It is mentioned as the place where the civil engineering activities are taking place, indicating that the video's theme is likely related to civil engineering education or practical training. The script mentions 'Bandura East Campus' and 'Building 25253,' suggesting a detailed exploration of the campus facilities.

💡Civil Engineering

Civil Engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment. In the context of the video, civil engineering is the main theme, as the script discusses activities related to concrete casting, which is a common practice in civil engineering projects.

💡Concrete

Concrete is a composite construction material made from aggregate, a binder (usually cement), water, and chemical additives. It is central to the video's narrative as the script describes the process of casting 30 MPa concrete, which involves measuring and mixing the correct quantities of cement, water, sand, and aggregates.

💡Mix Design

Mix design in civil engineering refers to the process of specifying the proper proportions of concrete ingredients to achieve the desired properties of the final product. The script mentions that the mix design is outlined in a lab manual, indicating that the video is about following a specific recipe to ensure the concrete meets certain strength requirements.

💡MPa (MegaPascal)

MPa stands for MegaPascal and is a unit of pressure or stress. In the context of the video, 30 MPa refers to the desired compressive strength of the concrete being cast. This is a key specification as it determines the proportions of the ingredients in the mix.

💡Aggregate

Aggregate refers to the granular materials like gravel, sand, or crushed stone that are used in construction to create concrete or other building materials. The script specifies the use of both fine and coarse aggregates, highlighting the importance of different sizes of aggregate in achieving the desired concrete properties.

💡Segregate

In the context of the video, segregate refers to the process of separating and measuring out the different components of the concrete mix. The script mentions measuring out water, cement, sand, and aggregate separately before combining them, which is a crucial step in ensuring the accuracy of the mix.

💡Concrete Mixer

A concrete mixer is a device that homogeneously combines cement, aggregate, sand, and water to form concrete. The video script describes using a small concrete mixer with a 60-liter capacity, which is selected based on the volume of the mix, emphasizing the importance of using the right equipment for the job.

💡Slump Test

The slump test is a simple test to measure the consistency or 'slump' of concrete, which indicates how much the concrete will settle and spread out after being poured. The script describes performing a slump test with a reading of 180 millimeters, which is a measure of the concrete's workability.

💡Curing

Curing is the process of maintaining optimal moisture and temperature conditions for newly placed concrete to strengthen and harden. The script mentions a water curing process where specimens are soaked in water for seven days, which is a common method to ensure the concrete gains its designed strength.

💡Curing Tank

A curing tank is a container used to hold concrete specimens during the curing process. The script describes placing demolded concrete samples into a curing tank, which is essential for maintaining the necessary conditions for the concrete to cure properly.

Highlights

Introduction to Bandura East Campus and the civil engineering lab.

Explanation of the process to cast 30 MPa concrete.

Outline of the ingredients and their required amounts for concrete mix.

Calculation of total volume and ingredient quantities based on mix design.

Measurement of cement, water, sand, and aggregate using a scale.

Use of the smallest concrete mixer with a 60-liter capacity.

Mixing of dry materials, including sand and aggregate, in the mixer.

Addition of cement to the mixer and subsequent mixing.

Introduction of water to the mixer to complete the concrete mix.

Conducting a slump test to measure the consistency of the concrete.

Filling and vibrating the mold to remove air bubbles and ensure uniformity.

Curing process of the concrete specimens in water for seven days.

Use of a curing tank for water curing of the concrete samples.

Preparation for demolding the specimens and transferring them to curing tanks.

Overview of the lab's process from mixing to curing and future testing.

Transcripts

hi everyone

today i'm here in the bandura campus in

particular bandura east campus and this

is where this is where our civil

engineering is

so i'm outside building 25253

so our lab is on the ground level of

this building good morning everyone so

we first want to understand

the ingredients required

required amount of ingredients so

basically concrete uh we're going to

cast 30 mpa concrete uh

30 mpa concrete so then we need to

measure the cement water sand and

aggregates so according to the mix

design as outline in the

lab manual so

then we need to understand we have four

specimens five specimens all together

then we have to add additional 25

then we calculate the total volume based

on that total volume then we can

calculate the required quantities of

each ingredients basically cement 5.91

kilograms water

one nine kilograms sand eight point

eight four kilograms and aggregate

twenty point two uh to one kilograms so

once we have all the calculations then

we can use this scale

then we can start measuring each

ingredient so for an example

so this is water

so the required level is

3.19 so including the bucket weight it

is around 3.65 so then we have the right

quantity

excuse me we have the right quantity in

water

similarly

we can measure all the other three

ingredients so this is called segregate

this is a 10 millimeter cross aggregate

this is fine aggregate we use a river

sand and this is the

general portland cement

so all the ingredients we measured based

on the

quantities we calculated

okay so this is our concrete mixer we

have

different sizes of concrete mixers in

concrete lab so this is the smallest

concrete mixer

which can carry

up to 60 liter of volume

so we selected based on the volume

of the calculation so first thing we

have

we have to mix all the dry materials

you can use sand

and pour into the mixer

[Applause]

this is first aggregate

so once we have all the finite create

and pulse aggregate inside the concrete

mixer then we can mix

around one to two minutes

[Music]

oh

[Music]

so

once we have a uh

aggregate mixing so then we can add

cement into the uh fine and force

aggregate

[Music]

so then you can mix that another one to

two minutes

[Music]

so

[Music]

so then we can add water

[Music]

so

[Music]

[Music]

so

foreign

[Music]

[Applause]

so

[Applause]

so our next one islam taste

then you need to stack the corn

that's enough so then we can tamp 25

blocks

then you can fill the next

one third

so one more

okay so then you need to come back only

that one third layer so then you have to

provide another 25 laws

then you can fill the last one third

and then you can provide another 25

blocks for that

the last one sir

then you need to lift the pole

you can place your phone

then with the roller

with the roller you can measure the

slump

high into the maximum point

so then reading will be

around

180

180 millimeters

so once you finish your slump test you

can go back into the bucket then you can

start

filling your mold

is a

small filling

with concrete and vibrating so

what we want to know uh

we want to fill first half of the moles

then we can

start vibration table for a few seconds

then while vibrating we can feel the

remaining half

so let's start with the first half

[Music]

so

[Applause]

yeah you can see john

yeah next we can complete the

we can fill

to the top level then we can vibrate it

again

[Applause]

up

so

[Applause]

oh your calculations are exactly right

did you add 25

so

now we have we have filled up to the top

level then we have to vibrate it

again for

months two minutes

until we remove all the air bubbles

so

then

you almost have a very uniform surface

in the top then you can leave all your

specimens somewhere in the safe side

for the another 24 hours once we have

all the things uh probably tomorrow the

same time we will come back and we will

demold all the things then we can put

into the uh concrete uh in curing tanks

so in the curing process is water curing

then we have to soak all the specimens

in water tank for seven days

until being tested

and this is example of curing tank so

once we demold all these specimens by

tomorrow

morning so then we can bring all

specimens into this curing tanks you can

have a look some of the previously

demold concrete samples are there so

then we have to keep all these uh

samples in cured uh during tank

until being tested in next week