Effects of Al and Fe powders on the formation of foamed cement obtained by phosphoric acid activation of volcanic ash

The present study aims to compare the effects of aluminum (Al) and iron (Fe) powders as a foaming agent in the synthesis of cement based on phosphoric acid activation of volcanic ash. The compressive strength, X-ray diffraction and microstructure were performed on specimens to elucidate the mechanism involved. The results obtained has proven that the reduction of compressive strength and mass are more prominent with the addition of Al than that of Fe. Also, the addition of Al and Fe induced respectively the formation of amorphous AlPO4 and FeHPO4. Thus, the formation of foams cements can be controlled by the addition of appropriate foaming agent.