How sidewalks and roads fall apart over many of years


By Casey Werner

Many roads, parking lots, and sidewalks on Long Island are in need of repair because of the inclement weather Long Island has had in recent years. This also includes many local colleges and universities on Long Island. Specifically, the Ammerman Campus in Selden has experienced these same problems with regard to their parking lots and adjoining sidewalks.
The current state of the sidewalks at the Selden Campus has been a concern of both the college and its students. The sidewalks are cracking and falling apart because of the severe weather that they have endured and how they were initially constructed. If not constructed properly, water can get under the concrete, freeze and cause it to lift which is called heaving. Concrete, the material that sidewalks are made of, needs to be mixed and applied a certain way in order for it to be very durable. “Concrete must be applied using three steps,” Dave Farrell, a land surveyor with Fehringer Surveying in Seaford, said. First, dirt or soil has to be flattened with a vibratory tamper until the softness of it becomes very hard and compact. After that, a sub base must be put down. The sub base consists of a layer of rocks, dirt, and recycled crushed concrete which are combined to make it solid. After the sub base is applied, this layer must be tamped as well. The final step is to pour the concrete over the first two layers. In between the concrete, there should be a layer of wire mesh. The mesh is used to make the concrete stronger and harder so it won’t break as easily. This creates a stronger surface and subsequently last longer.
Many cracks arise from what is underneath the concrete because it was never hard enough to hold the weight. This under layer was soft and not tamped down completely. In addition, sidewalks have been known to crack when tree roots grow beneath the surface yet close enough to the surface to lift the concrete. These roots are called surface roots and they grow across the ground and not down. As roots grow across the ground, the soil beneath the concrete becomes weak and the concrete can crack, lift or cave in. These factors all contribute to the decline of the sidewalk whereby walking on the sidewalk now becomes a safety issue.
Roads and parking lots that are paved with asphalt have faced similar problems in the form of potholes and cracks. These too are caused by inclement weather but the construction of these venues also plays a role. “As with sidewalks, the sub base of a parking lot or road must be compacted to a very hard state with a roller or a flat plate tamper,” Chimienti said, a contractor with Chimienti Construction in Saint James. This will make it easier and a lot faster to harden the sub base. Once the sub base is hardened the asphalt is put down with two layers; each layer being at least two inches thick. Asphalt is comprised of tar, liquid asphalt, sand and aggregate. The asphalt doesn’t need to be reinforced with mesh as with the concrete. Concrete is made up of cement, sand, aggregate and water and needs to be cured for a long period of time. On the other hand, asphalt does not need to be cured and can be used almost immediately.
There are various ways that potholes can be formed in the asphalt. Water can seep in through cracks caused by improper installation of the asphalt and/or sub base. This in turn will loosen the asphalt; making it weaker so that pot holes are more prone to forming. This is why it is imperative that two layers of asphalt are used. “The temperature is a large factor in the installation of asphalt,” Porpora said. Asphalt cannot be applied in the winter as the asphalt and the tar become stiff and do not adhere to the sub base and each other. It needs to be put down at a certain temperature so that problems will not occur over time.
The New York City Department of Transportation uses broken glass as an additive to stabilize the asphalt. That broken glass is the sparkle you see while driving on the road. On Long Island, the preferable asphalt mixture is tar, asphalt, and aggregate. Many years ago, macadam and bituminous were used to make ashphalt, a mixture that consisted of ash. Today, asphalt is used without the ash.
As we have seen over time, our precious roads and sidewalks have not weathered its storms very well. Construction companies have to be more cognizant of the proper procedures of constructing roads and sidewalks and not always trying to cut corners because money is being saved. The pedestrian in addition to the motorist should be an important consideration when building our roads and sidewalks.

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