Ash from Vegetable Waste Used for Economic Production of Low to High Strength Hydraulic Binders

摘要

Some vegetable wastes contain relatively large amounts of silica. One of the most promising examples is rice husk. Since rice is a major crop among many of the developing countries, it is in large quantities available. Its ash can be produced without using expensive fuels -such as in case of Portland cement. During incineration heat is even released which could eventually be transformed into mechanical energy for grinding the ash. An artificial pozzolan is obtained, which can be combined with lime to yield an hydraulic binder of lower quality. Kaolin clay - when available - could be added during incineration to improve the binder quality. At the other end of the spectrum, Portland cement can be blended by finely-ground rice husk ash to produce with a water reducing agent at low water to cement ratios high strength concretes. Blending with the incinerated kaolin can further increase cost effectiveness. The paper concentrates on the RHA technology but also gives a survey of obtained strength data.