Produktong Pinoy: Rice husk ash good for mixing with cement

A Filipino scientist has developed a process by which rice husk ash may be used as a supplementary material for producing cement.

Marshal Calica, Jr., a researcher at Saint Louis College in San Fernando City, La Union, has proven that rice husk ash may be used as an admixture in producing cement paste and concrete.

His study, entitled, “Influence of Rice Husk Ash as Supplementary Material in Cement Paste and Concrete,” is a finalist in a research and development (R & D) competition for industry and energy held in San Fernando City, La Union. According to Calica, 10 percent rice husk ash may be used as a supplementary material for producing cement, thereby helping save cost for contruction materials at R20 per bag of cement.

“You can replace some amount of cement (up to 10 percent) without sacrificing the strength of the concrete,” Calica disclosed.

The researcher said rice husk ash contains silica which serves as a binder in producing cement. It is environment-friendly as it aims to reduce waste coming from rice husk.”It can increase the permeability of the concrete,” Calica said.

He however said the process using rice husk ash as a supplementary material takes longer to harden than ordinary cement.

“But it doesn’t mean that it is disadvantageous because there are situations when cement needs longer hardening,” Calica explained.

“As structural designers, the main parameter in the design of concrete structures is compressive strength of the concrete,” he added.

Initial setting time of cement without rice husk ash takes about 97 minutes and about 108 minutes with rice husk ash.

“Generally, rice husk ash prolongs or lengthens the setting time of the cement paste and therefore, it is considered as a retarder,” Calica explained.

“Concrete mixture containing rice husk ash as supplementary material reduces the slump of unhardened concrete,” he added.

source:http://www.abs-cbnglobal.com