CIVE1265 Concrete lab Part 2

Summary

The video script details a comprehensive guide on concrete testing, focusing on compressive, split intensity, and flexural testing. It explains the standard sample sizes for different standards, such as Australian and U.S. standards favoring 200mm x 100mm cylinders, while UK and European standards prefer 100mm or 150mm cubes. The script also describes the use of an MTS machine for testing, the setup for split intensity testing with a special frame, and the four-point bending test arrangement. The video provides a practical demonstration of these tests, enhancing understanding of concrete strength evaluation.

Takeaways

• 🗓️ The script describes a process of testing concrete specimens after a curing period of seven days.
• 🏗️ Three types of concrete tests are mentioned: compressive testing, split intensity testing, and flexural (bending) testing.
• 📏 Compressive testing can be conducted on two different sample sizes: 200mm height by 100mm diameter cylinders or cubes of 100mm or 150mm.
• 🌐 There are regional differences in standard sample sizes, with Australia and the U.S. favoring cylinders and the UK and Europe favoring cubes.
• 📊 Compressive strength readings can vary depending on whether cylinders or cubes are used, so it's important to specify the specimen type when presenting results.
• 🔩 The script introduces a larger cylinder with 300mm height and 150mm diameter, which is used for split intensity testing.
• 🔄 Split intensity testing involves applying a horizontal compression load that converts into an axial tensile force, causing the cylinder to split.
• 🛠️ The script mentions the use of an MTS machine for testing, capable of applying up to 3000 Newtons of force, with the possibility of upgrading for higher loads.
• 🔧 A special frame is required for split intensity testing, which is different from the standard compressive testing setup.
• 🔄 The script also discusses four-point bending testing, which requires a specific framework with two points of loading and two roller supports.

Q & A

What types of concrete testing are mentioned in the script?

The script mentions three types of concrete testing: compressive testing, split intensity testing, and flexural or bending testing.

What are the standard sample sizes for compressive testing according to the script?

The standard sample sizes for compressive testing mentioned are 200 millimeter height and 100 millimeter diameter cylinders, and 100 or 150 millimeter cubes.

Why might there be different compressive strength values for cylinders and cubes?

Different compressive strength values for cylinders and cubes may be due to the different shapes and sizes of the samples, which can affect the stress distribution during testing.

What is the purpose of the larger cylinder with 300 millimeter height and 150 millimeter diameter?

The larger cylinder with 300 millimeter height and 150 millimeter diameter is used for split intensity testing, which measures the tensile strength of the concrete indirectly.

How does the split intensity testing frame work?

The split intensity testing frame applies a horizontal compression load to the cylinder, which is then converted into an axial tensile force, causing the cylinder to split into two parts.

What is the role of timber bits in the split intensity test?

Timber bits are placed on either side of the cylinder in the split intensity test frame to ensure proper alignment and to prevent the cylinder from moving during the test.

What is the four-point bending test and how is it set up?

The four-point bending test is a flexural test that measures the bending strength of a specimen. It is set up with two points of load application and two roller supports, creating a setup with two spans.

What is the maximum force the MTS machine used in the script can apply?

The MTS machine used in the script can apply a maximum force of 3000 Newtons, with the possibility of upgrading for higher forces if required.

How does the compressive strength test work on the MTS machine?

In the compressive strength test on the MTS machine, a constant pressure is applied to the top surface of the cylinder by the movable arm until the cylinder is crushed.

What is the significance of presenting the type of specimen (cylinder or cube) when reporting compressive strength?

Presenting the type of specimen (cylinder or cube) when reporting compressive strength is significant because it provides context for the results, as different specimen shapes can yield different strength values.

Outlines

00:00

🏗️ Concrete Testing Procedures

This paragraph discusses the various tests conducted on concrete specimens after a week of curing. The narrator explains three types of tests: compressive testing, split intensity testing, and flexural (bending) testing. The standard sample sizes for compressive testing are highlighted, which include 200mm height and 100mm diameter cylinders following Australian or U.S. standards, and 100mm or 150mm cubes following UK or European standards. The importance of specifying the specimen type when reporting compressive strength is emphasized. The paragraph also introduces larger cylinders of 300mm height and 150mm diameter for split intensity testing and mentions the use of a different frame for applying horizontal compression load. The narrator promises to explain more about split intensity testing during the actual demonstration. Additionally, a four-point bending test setup is mentioned, which will be elaborated upon later.

05:02

🔧 Setting Up for Split and Flexural Testing

The second paragraph focuses on the preparation for split and flexural (bending) tests. The narrator describes the process of placing a cylinder into a special frame for the split intensity test, which involves using two timber bits for support. The arrangement is designed to apply a compression force vertically to the cylinder, which then translates into a horizontal or lateral direction, converting into axial tensile force as per equations provided in a handout. The narrator demonstrates how the cylinder splits into two parts, hence the name 'split intensity' or 'indirect tensile' test. The paragraph concludes with a brief introduction to the setup for the four-point bending test, which includes a framework with two points of loading and two roller supports, essential for conducting the flexural test.

Keywords

💡Concrete Casting

Concrete casting is the process of pouring liquid concrete into a mold or formwork to create a desired shape. In the video, this process is mentioned as having been completed the previous week, and now the cured specimens are ready for testing. The casting process is fundamental to the construction industry as it allows for the creation of various structural elements.

💡Compressive Testing

Compressive testing is a method used to determine the compressive strength of a material, such as concrete. The video discusses this test as one of the standard procedures for evaluating the quality of concrete specimens. The test involves applying pressure to the specimen until it fails, providing a measure of its strength. This is crucial for ensuring that the concrete used in construction can withstand the loads it will be subjected to.

💡Split Intensity Testing

Split intensity testing, also known as the indirect tensile test, is a method used to measure the tensile strength of a material by applying a compressive load that induces a tensile stress, causing the specimen to split. The video describes this test using a special frame where a cylinder is placed, and a horizontal compressive load is applied, which is then converted into an axial tensile force. This test is important for understanding how materials behave under tensile stresses.

💡Flexural Testing

Flexural testing, also referred to as bending testing, is used to determine the bending strength of a material. In the video, a four-point bending test is mentioned, which involves applying loads at two points on a specimen and supporting it at two other points to create a bending moment. This test is essential for evaluating the material's ability to resist deformation and failure under bending loads, which is a common type of stress in construction.

💡Cylinders and Cubes

Cylinders and cubes are the two different shapes of concrete specimens used for compressive strength testing. The video specifies that cylinders are typically 200mm in height and 100mm in diameter, following Australian or U.S. standards, while cubes, which are more common in UK and European standards, can be 100mm or 150mm on each side. The choice of specimen shape affects the compressive strength results, so it's important to specify which type was tested.

💡Australian Standards

Australian Standards refer to the set of rules and guidelines that dictate the quality and safety of materials and products in Australia. In the context of the video, these standards are mentioned as influencing the choice of specimen shape for compressive testing, favoring the use of cylinders. Adhering to such standards is critical for ensuring that construction materials meet the required performance and safety criteria.

💡UK Standards

UK Standards, similar to Australian Standards, are a set of guidelines that specify the requirements for various materials and products, including concrete. The video notes that UK and European standards often use cube-shaped specimens for compressive strength testing. Following these standards is essential for ensuring that construction materials are suitable for use in the UK and Europe.

💡MTS Machine

The MTS machine, or Material Testing System, is a type of universal testing machine used to perform various material tests, including compression, tension, and flexure. In the video, the MTS machine is described as the equipment that will be used to test all the concrete specimens, with a maximum capacity of 3000 Newtons. This machine is vital for accurately measuring the strength and performance of materials under controlled laboratory conditions.

💡Load Cell

A load cell is a device used to measure force, weight, tension, pressure, and other types of mechanical loads. In the video, load cells are mentioned as part of the MTS machine and the split intensity testing frame. They are crucial for accurately applying and measuring the forces during the tests, ensuring that the results are reliable and consistent.

💡Four-Point Bending Test

The four-point bending test is a variation of the flexural test where the specimen is subjected to loads at two points, with supports at two additional points. This setup creates a region of the specimen that is subjected to bending without direct compressive or tensile forces, allowing for the measurement of the material's flexural strength. The video describes the specific arrangement of the test frame and the importance of this test in evaluating the bending performance of concrete.

Highlights

Introduction to concrete casting and testing after a seven-day cure.

Three types of concrete testing: compressive, split intensity, and flexural (bending).

Standard sample sizes for compressive testing include 200mm height and 100mm diameter cylinders.

Different standards for sample sizes: Australian/U.S. standards prefer cylinders, while UK/European standards prefer cubes.

Compressive strength readings vary depending on whether cylinders or cubes are tested.

Larger cylinders of 300mm height and 150mm diameter are used for split intensity testing.

Split intensity testing involves a special frame to apply horizontal compression load.

Flexural testing, also known as bending testing, uses a four-point bending test setup.

Explanation of the MTS machine used for testing concrete specimens with a maximum capacity of 3000 Newton.

Demonstration of compressive strength testing on a cylinder using the MTS machine.

Split intensity testing setup with a special frame and the use of timber bits.

Conversion of lateral compression force into axial tensile force during split testing.

Observation of the cylinder splitting into two parts during split intensity testing.

Setup for four-point bending test with two pin supports and one roller support.

Overview of the testing process and the importance of presenting accurate test specimen information.

Transcripts

hi good morning everyone so

we have a concrete casting last week now

uh after seven days cured specimens we

going to test so basically we have to do

3 concrete testing compressive testing

split intensity testing and flexural or

bending testing so this is the standard

sample size for the compressive testing

we have two different size of samples we

can select for uh compression so one is

cylinder this is a 200 millimeter height

and 100 millimeter

diameter cylinders so this is basically

australian standards or u.s standards

generally follows concrete cylinders for

the compressive strength but when we

consider uh

uk standards and european standard they

are more towards the cubes so it can be

100

millimeter cubes or 150 millimeter cubes

so instead of this concrete cylinders so

two different values you will get for

the compressive strength when you say uh

when you are testing for the cylinders

or else cube so make sure you need to

present your

compressive strength reading what

specimens you have tested either

cylinders or cubes

the next one is the larger cylinder so

this one three millimeter 300 millimeter

height

150 millimeter diameter so this

uh

we can use for the split intensity

testing so i will explain more on the

split intensity testing while we are

doing the things so we have a different

frame then we have to uh provide

horizontal load horizontal compression

load that will be transferred to the

axial of direction and convert into the

axial tensile force

the other one is

flexural

testing so in other words we are saying

bend in testing so we are this is a four

point bending test so this is also have

a separate arrangement frame so i will

make sure to explain bit more during the

testing stage

thank you

so

[Applause]

okay so

this is the mts machine so we're going

to use that testing machine

to test all the concrete specimens today

so which can go up to maximum three

thousand uh three thousand newton so we

can also upgrade into the further couple

of thousands if required so

then this is a compressive strength uh

cylinder so we are compressing in

both directions so

this arm can be this is a fixed arm this

is the movable arm the lower cell so it

will apply constant pressure to your

cylinder the top surface so until being

crushed

first one

hey

so

[Music]

so this is the

split in testing we're going to do this

is the special frame so we required for

this particular testing

so

now we need to place the cylinder into

the frame

so before that we need

two timber bits

we have to keep

one in here

the other

on the top

okay this is the

uh specific arrangement for the split

intensive taste

[Music]

okay this is the pool arrangement

so we are providing compression force

here again so with the upper load cell

so you can see when you do the testing

when we do the testing

then you will come you will provide the

compression force to the cylinder in

vertically it will transfer to this

middle axis

to the horizontal direction or the

lateral direction so then it will

convert then equations provided in this

handout

can convert that

lateral compression force into the axial

tensile force

so

so

can you see they exactly split into the

two parts so that's why we are telling

this taste as a split intensive

sometimes we call indirect tensile taste

these are the two split parts

okay this is the going to test uh

bending or the flexural testing this is

the framework we required so we have

four point bending testing this is two

points and we'll provide two roll uh one

pin support and one roller supports so

that's the arrangement for four point

bending test

so

[Music]

you