KAUAI, HAWAII, November 16, 2007: Kauai’s Hindu temple got a foundation built to last 1,000 years, and it just took longer to dry.
Sure, builders love modern reinforced concrete which reaches full strength in two days, whereas the ancient fly ash concrete takes three months. Yet, the quick-curing concrete only lasts for decades, while the other lasts for millennia. When the temple’s Indian architect specified strength and longevity, it was clear that modern concrete simply wouldn’t do, nor would “modern” builders attempt the experiment… which is where professor Kumar Mehta came in.
Mehta knows concrete. Returning to the mixture of cement and fly ash used by ancient Greeks and Romans, Mehta fashioned a foundation in which 60% of the portland cement is replaced with fly ash. To create the two 6,500sf pads for the stone temple, Mehta’s team used only 80 tons of cement, instead of the 230 tons of cement and 75 tons of steel required with conventional reinforced concrete.
With cement production now contributing more than 6% of global greenhouse gases and growing fast, alternative construction methods are mandatory. By mixing in some fly ash, we could reduce cement use by half.
Prof Mehta says, “This demonstrates a revolutionary method of concrete construction which, if widely adopted could save millions of dollars a year, create structures to last far longer than they do now and substantially reduce the introduction of carbon dioxide to the atmosphere.”