The effect of local pozzolans and lime additions on the mineralogical, physical and mechanical properties of compressed earth blocks in Argentina

The purpose of this research is to evaluate the mineralogical, physical and mechanical properties of compressed earth blocks (CEBs) stabilized with lime and mineral admixtures easily obtained in Argentina: natural pozzolans and brick powder. The mineralogical composition and pozzolanic potential of the admixtures were determined, as well as the development of hydraulic phases upon reaction with calcium hydroxide (lime), adding emphasis on the formation of hydrated cementing compounds. Samples with different percentages of lime and mineral additions were prepared to assess their compressive strength, wet erosion resistance and water absorption, and the results were contrasted with those of their counterparts, stabilized exclusively with lime or cement. The results obtained imply that both the brick powder and pozzolans used have pozzolanic properties and that, in combination with calcium hydroxide, they form amorphous phases of C-(A)-S-H. However, the use of small amounts of both additions in combination with hydrated air lime in the manufacture of CEBs adversely affected their physical and mechanical properties, compared to CEB samples stabilized only with hydrated air lime.