Study of earth-based materials for manufacturing compaction process

Abstract

The aim of this study is to develop a characterization test for the purpose of determining the consistency of the earth-based material adapted to produce compacted earth bricks (CEB). Existing tests have often been designed for plastic or fluid earth materials, which is not the case for compact earth materials of interest in the present study. This study includes the different methods of characterization for the shaping of these materials, such as: Atterberg limits, Carazas test, and dropped ball test. The earth-based mix studied has a plastic limit of 20%, a liquid limit of 42%, and a plasticity index of 22%. Therefore, the mix can be classified as a medium plasticity clay. The Carazas and dropped ball tests reveal that the manufacturing water content must be between 12% and 16% to ensure proper adaptation to shaping by compaction. However, these characterization methods are neither sufficient nor accurate enough to quantify the consistency to the manufacturing of CEB. For this purpose, to measure this consistency, a plunger penetration test with surcharge is developed. It could be shown that the plunger impact depth corresponding to the suitable consistency of CEB should be in the range of 6–10 mm. In order to confirm these results and select the suitable water content for production, the compressive strength of CEB at different water content (12%–20%) is measured; results indicate that the highest compressive strength is noted for a water content of 14%, which corresponds to a surcharged plunger impact depth of 8 mm.