An Investigation on the Determination of Compressive Strength of Poured-earth/Earth-cobs (PEEC) Masonry Wall

Excessive shrinkage as the cause of low compressive strength associated with the monolithic poured earth method of earth construction is always a discouraging factor for professionals in the built environment. Poured earth is becoming more widely used to construct buildings worldwide and has gained popularity as an aesthetically pleasing, low cost and sustainable building technique. Poured earth structures could be monolithic if cast completely from the same earth slurry or masonry if produced from two heterogeneous materials. Therefore, this research adopted spherical earthcobs as plums in poured-earth for the construction of earth-based masonry wall. Three different types of earth-cobs and four different types of poured-earth were produced at different percentages of cement in the mixes. Prisms with a height-to-thickness ratio of 2.1 were used to determine the compressive strength of the Poured-Earth/Earth-Cob (PEEC) masonry wall. Twelve different types of cast prisms were produced from different combinations of poured-earth and earth-cobs. Additional four types of prisms were also produced by using poured-earth slurries alone for compressive strength compared with the types that have earth cobs. The result of IRA shows that the suction effect of the spherical earth-cobs through capillary action increases with an increase in cement added to the mixes and increases with time. The results of the compressive strength of the masonry wall samples show improved strength and approximately total elimination of shrinkage compared with the monolithic poured earth wall. The research, therefore, recommends the use of poured-earth with earth cobs as plums for the construction of earth masonry wall.