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The Skid Resistance Test For Concrete Pavement
The main objective of this test is to decide the effect of aggregate properties on the skid resistance of concrete pavements. The specimens from different aggregates had been cast into small concrete slabs and which were tested to figure out their wear and tear characteristics. A test method is established for identifying a suitable skid resistant material.
- To evaluate the impact of exposed coarse aggregates, aggregate size, and abrasives on the friction characteristics of concrete.
- To establish a procedure for determining the potential skid resistance of concrete aggregates before casting pavement.
Test Equipment and Apparatus
- The skid-resistance tester
- Clean tap water in the container for wetting the surfaces.
- Electronic thermometer
- Spirit level or steel tape for measuring the gradient
- Non-metal stiff hand brush for cleaning the surface
- Portable anemometer
Set up of Portable Skid-Resistance Tester
- The base level was placed on the recycled concrete aggregate testing specimen slab (RCA). With the help of spirit level and adjustable screw level it properly.
- The head was raised by knobs on the rack and pinion at the rear of the tester. The head was re-clamped as it raised to a suitable height.
- The zero setting was checked by releasing and catching the pendulum on its return swing. Then the pendulum was taken to its release position and the pointer reading was noticed.
- Now, the pendulum hung free and the rubber slider was raised using the lifting handle. Then the spacer was placed beneath the lifting handle screw. The head of a tester was lowered until the slider touched the pavement surface and clamped in the position. The pendulum was raised and the spacer was removed.
- The sliding length of the rubber slider was checked by lowering the pendulum until the slider touched the specimen surface and marked its position. The rubber slider was raised by lifting handle and then the pendulum was moved up on the left side. The pendulum was lowered until the slider touched the surface again. Sliding distance was checked and marked on the sides with the help of the gauge
The tester was set up on RCA specimen as described above (same procedure will be used for granite specimen)
The specimen surface was assured that it was free from dirt and then wet the surface and rubber slider.
The temperature of the water was noted.
The pendulum was placed in its release position and the pointer was bought up to its stop position.
The pendulum was released by pressing its release button and caught it on its return before it struck to surface.
The reading was noted, as indicated by the pointer and then pendulum was replaced in its release position.
This was repeated for 10 times and the average result was taken.
The tester was then turned in 900 on the specimen and again same procedure was repeated from the setting up skid resistance tester.
Testing of granite specimen was followed by the same procedure as RCA specimen.
Data and Analysis
Recycled concrete aggregate slab - Side 1
Recycled concrete aggregate slab - Side 2
Granite Slab - Side 1
Granite Slab - Side 2
The PTV values of both the specimen were found by the following formula:-
PTV = ∑ (V1 + V2 + V3 + V4 + V5) / 10
V1 to V5 are individual values for each swing
- There was an error of 0.5 in the skid resistance tester, which was minimized by deducting it from every reading.
- The Chainage: The marker post is usually utilized for the position of the measurement on the road, which is referred as a Chainage. The Chainage commonly measured from an established point to the other end of the road. It always increases in one direction of the road and decreases in other.
- The distance from the edge of the road (curb): Kerbs are a very important aspect of road design and construction. They are essential as they help in the prevention of water from penetrating into the roadway, providing pedestrian and vehicle boundary. They also create a raised anti-vehicle barrier while making a channel for surface water drainage. Their distance is needed for the safe distance between a vehicle and the edge of the road.
- To make dry contact between tire and road, there should be a tread pattern in the tire. The skid- resistance of a well-treaded tire on a smooth road could be double that of a similar road with a smooth tire. It doesn’t help to have patterns on both tire and road. But, on the coarse textured road, slightly lower results were found. Another demand to assure a high skidding resistance in wet condition is that all stones should have a right shape.
- If one has to construct a road in a cold weather then the concrete road would be suitable, but one thing needs to assured that the sub-base of the road should be properly laid out with gravels. Otherwise, there would be a risk of cracking due to frost heaves. If the road is needed to be constructed in hot weather, then bituminous roadway would be suitable. Bituminous roads are cheaper compared to concrete roads. However, bituminous roads require more care over the period of time to protect it. Bituminous roads require sealing at least once in every 3-5 years. While carrying out the test it should be checked that bituminous road should not always be black in color and the concrete road should not always be off-white. Both the roads can be tinted to different colors.
- Another method for determining skid resistance of a surface is a sideway-force coefficient routine investigation machine (SCRIM). This method determines the road skid resistance properties of a surface by measurement of the sideway-force coefficient at a controlled pace. This method has been established for the road use.
This test was carried out to determine the effect of aggregate properties on the skid resistance of concrete pavements.
First, the test was carried out on the recycled concrete aggregate slab (RCA) on its wet surface. On the first five swings average reading was noted 67.7 then the reading of following five swings was noted 66.4. That means there was more friction on first five swings then gradually it reduced and came to 66.4.
Second, the same test was carried out on the granite slab with a wet surface. On the first five swings average reading was noted 73.4 then the reading of following five swings noted 71.2. That means there was more friction on the first five swings then gradually it reduced and came to 71.2. From the test, it has been determined that granite surface has a more friction than the recycled concrete aggregate surface.
From the study, it has been marked out that those sand particles larger than 0.297mm sieve size give higher skid resistance values than the smaller size particles. A wonderful surface could be got by fresh concrete by means of a broom or belt finish. The exposed particles of sand produced by these finishes are essential to the resistance of the concrete to skidding.
Skid Resistance Test
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© 2017 Ashish Dadgaa