STUDY ON PROPERTIES OF CONCRETE MIXED WITH RICE HUSK ASH ADSORBING HEAVY METALS
Keywords:Rice husk ash, Recycling, Concrete admixture, Heavy metals
Goals 12 of the Sustainable Development Goals (SDGs), “Sustainable Consumption and Production”, aims to achieve “Drastic reduction of waste generation through the prevention, reduction, recycling and reuse of waste” by 2030. In Asia, more than 100 million tons of rice husk are discharged annually. Although they are utilized for biomass power generation as reuse, the generation of wastes has not been drastically reduced. Therefore, it is necessary to develop a method to realize a significant reduction of rice husk. The rice husk has the following features; it has the adsorption performance for heavy metals and incinerated rice husk contains a large amount of amorphous silica, which may increase the strength of concrete. Thus, firstly, untreated rice husk is utilized as an adsorbent for heavy metals. After that, it is used for biomass power generation to reduce its volume. Since heavy metals that remained in the rice husk are concentrated at this stage, the rice husk ash used for biomass power generation is mixed as a fine aggregate of concrete instead of being discarded as it is. In this study, fresh properties are examined by slump test and air content test, hardening property is investigated by compressive strength test, and harmful substance elution is evaluated by dissolution test. As the result, the concrete has fresh properties with no problem in construction, the concrete mixed with rice husk ash has a higher compressive strength than ordinary concrete, and no harmful substance is eluted from the concrete mixed with rice husk ash.