老标准新概念：废旧轮胎制透水混凝土（中英文）

　　用废旧轮胎制成透水混凝土，可让水通过。

　　纽约希垦纳特迪市的Ashraf Ghaly 教授在高校联盟实验室进行了一个实验，他把一大块实验用混凝土放在一个盆上面，他的学生Andrew Heiser 从几英尺高处向下倒水，然后两个研究者欣喜的看到：样品就象筛子一样开始漏水。

　　Ghaly 和 Heiser 正在做一个发展一种理想的透水混凝土的课题，而这种混凝土是用回收再利用的轮胎橡胶为主要成分。

　　透水混凝土是多孔的、用来减少复杂的排水系统和确保拓宽路面不会干扰地下水供应。Ghaly解释说“传统的混凝土是防渗的，经常需要用斜坡和排水系统来防止雨水和融化后的雪水积累在表面上，但是用透水混凝土做普通路面材料，所有的雨水都可以通过路面渗透到地下含水层。”Ghaly和Heiser实验了用不同比例的砂砾石和橡胶成分的组合，观察水的渗透速度和样本块的强度。Ghaly.说“这种平衡很微妙，因为如果你希望强度大，就要减少孔；如果你希望排水性好，就需要更多的空，而这又会减少强度。

 

　　本月，Ghaly和Heiser将他们的一些实验移到户外，在Memorial Fieldhouse 联盟附近的一个人行道上安装了一个15英尺长的测试点。三种不同配合比的混凝土一起铺在碎石基层上。每5英尺铺设的混凝土橡胶取代砂的比例都不同。有了户外的样本，他们就可以更好的演示这种混凝土在现实中是怎样的工作原理，包括寒冷的冬天和炎热的夏天的情况。

　　Heiser 说他很乐意帮助Ghaly研究，因为期望这个研究可以增强环境友好型建筑的设计。他说：“透水混凝土已经具有了一系列的环保效益，而废旧轮胎回收作为组成成分更增添了绿色成分。最主要的是加入了橡胶。现在每个人都越来越关注环保，而这是一个能创造一种新的环保方法的机会。”

　　美国每年产生数千万吨的废旧轮胎，切碎橡胶并使用它们生产混凝土可以避免用有污染的方法来处理废旧轮胎，如焚烧会污染空气、堆放会孳生蚊虫。同时，研究人员说，橡胶有助于改善透水混凝土的功能，使它更有弹性，减少冻结和冻融循环造成的恶化。

　　Ghaly指出，混凝土的孔隙使自然滋生的微有机体得以生长，这将有助于水通过混凝土时的过滤和净化。

　　Heiser 表示，透水混凝土还有助干屏蔽夏天拓宽的路面散发的额外热量——即“热岛效应”，可以使城市居民关掉冷气机，节省能源。

　　Ghaly 原来的专业是土木工程，他说他在大约10年前对环境相关的研究产生了兴趣。他作为学院联盟的一员15年，两年前做富布莱特学者时，开始用回收材料来进行他的兴趣研究，为他的母语国家——埃及，发展新的建筑材料。

 

　　Heiser，来自威彻斯特县，在去年的研讨会上介绍了该橡胶混凝土项目，并期待着与Ghaly进行进一步的研究。他也是该项目的主要推动者。他向学院的设施工作人员提出了在人行道实验的想法，现在他将推广这种新混凝土的使用和用途。他说“希望我们可以让学校看到这是一条非常环保的人行道。希望这仅是透水橡胶混凝土的开始”

　　"Pervious" concrete, made with recycled tires, lets water pass through
 
　　(SCHENECTADY, New York) -- Professor Ashraf Ghaly held a chunk of experimental concrete over a pan in his Union College lab while student Andrew Heiser poured out a stream of water from a few inches above.
 
　　The sample leaked like a sieve.  The two researchers couldn't have been more pleased.

　　Ghaly and Heiser are on a mission to develop an ideal version of "pervious" concrete that includes recycled tire rubber as one of its main ingredients.

　　Pervious concrete is designed to be porous, reducing the need for complicated drainage systems and helping to ensure that expanses of the pavement won't interfere with supplies to the groundwater below.

　　"Traditional concrete is impervious," often requiring slopes and drainage systems to prevent water from rain and snow melt from accumulating on the surface, Ghaly explained. But with pervious versions of the common paving material, "all the rain can percolate through the surface, charging the underground aquifer."

　　Ghaly and Heiser have experimented with various proportions of sand, gravel and rubber content in the lab, observing how quickly the water passes through and how well sample chunks hold up when extreme pressure is applied.

　　"It's a delicate balancing act, because if you want to have more strength, it needs to be less porous. When it is more porous, there is less strength," said Ghaly.

　　This month, the professor and student moved some of their experimental work outdoors, installing a 15-foot-long test sidewalk near Union's Memorial Fieldhouse. It has three versions of the concrete mix on a crushed stone base.

　　Each 5-foot section includes a different amount of pulverized rubber replacing sand in the mix.

　　With the outdoor samples, they'll be able to better demonstrate how the concrete performs under real-world conditions, including chilly upstate winters and hot summer days.

　　Heiser said he was enthused about helping with Ghaly's research because of the prospects for enhancing environmentally friendly construction designs. Pervious concrete already offers a number of environmental benefits, he said, and using recycled tire waste as one of the ingredients adds a bit of green gravy to the recipe.

　　"The big thing is adding rubber," he said. "Everyone is getting on the green bandwagon right now. This is a chance to help do something that's not already out there."

　　With tens of millions of tires being discarded by U.S. drivers each year, shredding that rubber and using it in concrete helps keep old tires away from harmful disposal methods like burning, which pollutes the air, and tire dumps, which can become prime breeding grounds for mosquitoes.

　　Meanwhile, the rubber contributes features that improve pervious concrete, the researchers said, making it more flexible and less vulnerable to deterioration during freeze-and-thaw cycles.

　　The porousness of the concrete allows for the growth of naturally occurring micro-organism, as well, which contributes to its ability to filter and purify the water flowing through, Ghaly noted.

　　Pervious concrete also can help stem the extra warmth given off by expanses of pavement on hot days -- known as the "heat island effect," -- which should enable city dwellers to turn down their air conditioners and save energy, Heiser said.

　　Ghaly's original field of training is in civil engineering, and he said he developed an interest in environmentally related research about 10 years ago.

　　A faculty member at Union for 15 years, he carried his interest in using recycled material to develop new construction materials to his native country, Egypt, as a Fulbright Scholar two years ago.

　　Heiser, who is from Westchester County, made three presentations on the rubberized concrete project at symposiums last year and is looking forward to further research with Ghaly during his upcoming senior year at Union.

　　He is also the project's chief promoter.

　　He pitched the idea of the experimental sidewalk to the college facilities staff, and now he'll be pushing for more extensive use of the new concrete.

　　"Hopefully, we can show the school that it's a very environmentally friendly sidewalk," he said. "I'm hopeful that this will be just a start for pervious rubberized concrete."