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�i? . �-i� � � �' __ . . �. _ . .: . (; ... � � :�i�a�`����� , <br />Aggregate is divided and placed intovbins according to size. Depending on the mixture of aggregate called <br />for, the bins automatically meter out the right amount of each size needed onto a conveyor belt. The belt <br />deposits the aggregate into a rotary dryer. This machine tumbles the aggregate through hot air to dry it thor- <br />oughly. A fuel burner is located at one end of the drum to provide a flame for heat. It is necessary to remove <br />the moisture from the aggregate so the asphalt cement will stick to the rock. Remember, water and asphalt do <br />not mix. After drying, the aggregate is sent to a mixing device where it is coated with heated asphalt cement <br />and thoroughly mixed. <br />� � : � , � , . � . �F � c., F i t ;��, 1 µ . ti �... F F F `� 11 �� � �. F, r - i ,. .. R t I �:� . - , � t �f . . . �• � /�'. E G. �• � <br />According to the EPA estimates, there are approximately 3,600 operating Hot Mix facilities throughout the <br />country. <br />�� , t �a, �F � ,t`�� f6!(z��� �.,���f�,���,' <br />Considering how large the United States is, there really are not a lot of facilities. This amounts to only one <br />facility for every 983 square miles. Approximately ninety-four percent of the roads in the U.S. are paved with <br />hot mix asphalt. Road maintenance and construction projects require over 550 million tons of hot mix asphalt <br />each year. Hot mix must be used quickly after being loaded into the haul truck because it hardens as it cools. <br />Cooling occurs during transport from the facility to the paving site. The haul distance needs to be as short <br />as possible to minimize the amount of heat lost during transport because only "hot" hot mix asphalt can be <br />worked (laid down by a paving machine and compacted by rollers). In addition, trucking is a large part of <br />road maintenance and construction costs. Minimizing haul distances will result in lower road paving costs. <br />-� <br />� _,. u �._ _.r�.: _.���..,�.. ___ . z. <br />a. _� __ ....� � �...�� ...�._ � �.,� _, .. . ���..0 ��-��,�.�.. <br />�.,� .� �: �.�_�.�._, � <br />