Type of concrete testing depends on type of concrete used, purpose of the concrete used and requirement from client. Concrete for concrete curb is not required to go through the concrete testing process because it’s just a light duty work, usually concrete testing used to test the concrete for commercial building, concrete bridges, and etc.

Types Of Concrete Testing

1) Cylinder Test
For Cylinder test, concrete is poured into a 6 x 12 inches cylinder (6 inches diameter, 12 inches height). The cylinders are usually plastic, like the ones below. The plastic cylinders filled with concrete are allowed to cure at 70 degrees Fahrenheit for 28 days.

Then each cylinder is loaded axially in a laboratory, the cylinder is stood up in a loading machine and an arm of the machine pushes down on the top of the cylinder until the cylinder breaks. The maximum amount of force the machine used on the cylinder is important, it tests the maximum strength of the concrete.

The compressive strength of the concrete, f’c (f¡¯c=P/A) where P is the load at which the cylinder failed A is the cross-sectional area of the cylinder, in this case, pi*r^2, where r is the radius of the cylinder. Cylinder concrete test is to be done in a closed room, no one will be around the concrete testing during the compressing process, because it’s very dangerous when the spoil concrete pieces will be flying everywhere.

2) Slump Test
Concrete Slump Test is another method of concrete testing, which is a easiest way of testing the concrete. Slump testing is a means of measuring the consistency of concrete using “slump cone”. The cone is made of galvanised metal with an 8-inch-diameter base, a 4-inch-diameter top and a 12-inch-height. The base and the top are open and parallel to each other and at right angles to the axis of the cone. This is the most economic way for concrete testing which don’t require any machine.

Source : SimScience | Tpub

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How To Build Concrete Landscape Edging By Using Miller MC250 & MC350

1) Mixing concrete by using concrete mixer or concrete batch. If by hand, wheelbarrow need to be used. Materials for concrete mixing such as cement, sand and water.

2) Once the concrete been mixed properly, put it in wheelbarrow. Move it to the place that the landscape curbing need to be done.

3) Start the concrete curbing machine (Miller MC250 & MC350).

4) Put in the ready mixed concrete into the concrete curbing machine.

5) A worker is pulling the concrete curbing machine, and the concrete landscape edging is built in shape. Another worker keep filling concrete into the concrete curbing machine.

6) Once the concrete landscape edging is done in shape, pull out the concrete curbing machine from the edging.

7) After that, a worker is smoothing the concrete landscape edging with a tool. Finishing the surface of concrete landscape edging and make it stable. Repeat this step for the whole concrete landscape edging.

8 ) Done!

Building concrete landscape edging by using concrete curbing machine is actually easy, it has lot of advantage such as time saving because these can be done in short period, minimum workers needed, low cost because of less time and worker, works done in clean and tidy condition, and etc. Most of the contractor like to use this method to build concrete landscape edging because it’s simple and low cost.

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Normally people uses concrete paving block to decorate their house’s external floor because concrete paving block has many colours and unique pattern. Paving block manufacturer mixes it with a few different of colour to make the pavers the look of natural stone, like granite or slate. Contractors use it on walkway as well.

How To Install Concrete Paving Block

1) Basecourse

Taking the existing sub-grade or soil conditions and the anticipated traffic loading into consideration, an adequate thickness of well compacted base course must be provided to ensure good pavement performance. Existing bitumen or concrete surfaces need not be removed and can act as good sub-grade.

2) Edge Restraint

Adequate edge restraints should be provided at this stage along the perimeter of paving area to prevent lateral movement of blocks. They may be in the form of concrete curbs or vertical edges of exiting structures.

3) Sand Bedding Layer

A layer of sand should be spread loose and screeded to a uniform thickness such that its compacted thickness would be approximately 30mm. It is important that the sand layer remains undisturbed prior to the laying of blocks.

4) Laying The Concrete Paving Blocks

Concrete paving blocks are placed side by side on the sand bed with gaps of approximately 2mm between adjoining blocks.

5) Cutting The Concrete Paving Blocks

Paving blocks an be cut to fit edges and awkward corners.

6) First Pavement Compaction

Block pavement is compacted with a hand-guided plate vibrator until it is firmly embedded in the sand layer.

7) Sand Filling

After first compaction, fine sand is brushed in to fill gaps in between paving blocks.

Second Pavement Compaction

Hand-guided plate vibrator is applied once again to ensure that sand filling in the gaps are fully compacted to stablize the block pavement. Steps 7 and 8 may need to be repeated until gaps are completely filled with fine sand. Once the remaining surface sand is removed, the block pavement is ready for use.

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In constructing a longer straight concrete curb at the construction site, it might requires more workers to complete the job on time. With that said, the cost will be increasing on this part. Other than this, contractor must ensures that the workers can complete the casting and make it in shape because the concrete will be fixed in certain period.

How To Build Concrete Curb By Hand

1) Build up the mold or formwork which is in concrete curb shape.

2) Mixing the concrete in correct mixture.

3) Pouring the concrete into the mold or formwork just now.

4) A few of workers are starting to smoothen the concrete curb with a timber plank. Workers must compact the concrete curb so that it won’t be collapsed or cracked easily. Workers must complete this task as soon as possible before the concrete fixed in shape.

5) After the workers have done the concrete works, they might need to take off the formwork or mold after the concrete is fixed in shape. Job is completed and workers have to continue other works like drainage system.

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The bridge design must be prepared by expert engineer and assisted by consultant. The bridge design must be able to carry all the work load or vehicle load, or else it might be collapsed. There was many cases of concrete bride collapsed due to design fault or usage of unknown materials, which is not only happened in my country but many other countries.

Concrete bridge can be constructed by using prestressed concrete, either pre-tension method or post-tension method. Pre-tension method means the tendon has been stressed and plug in into the concrete bridge before doing concreting. Post-tension method means the tendon is stressed by the machine after it has been concreting in the concrete bridge. Prestressed concrete are very famous and mostly been used in bridge construction, the purpose of using prestressed concrete is to increase the strength of the tendon or reinforcement bar, so that it can carry and support the load on the concrete bridge.

How To Build A Bridge?

I’ll be roughly explaining on how to build a bridge. There will be 5 simple sketches about how to build a bridge. I get the sketches from my current tender in Bahrain. So, this will be the procedure of constructing a concrete bridge in Bahrain. The procedures are almost the same with my country, I think it’s the standard method and procedure of constructing concrete bridge for all the countries.

1) The bored piles for the abutments are installed. The bored piles are drilled into the soil, bored piles are used because of the status of the soil is not stable, so bored piles are used to strengthening the soil. It’s one type of ground treatment.

2) The abutments and wingwalls are constructed.

3) Bearings installed. Bearings are used to reduce the vibration when vehicle drive through the concrete bridge so that the concrete will not crack.

4) Submerged drainage pipes are installed as a drainage system to allow the rain water flows. After that, the channel below the bridge is filled with sand.

5) Superstructure is cast and prestressed sand removed. The superstructure also known as concrete beam. There is a few types of concrete beam like : U-Beam, T-Beam, cast-in-situ beam and also precast beam.

After that, all the necessary works like deck slab, pavement works, road works, parapet, railing and drainage works will be constructed. All the materials must be tested before it’s used to construct the concrete bridge so that the bridge contractor can construct a perfect and high quality concrete bridge. Cost saving is very important in construction but safety is the most important in construction as well.

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