Architectural Engineering


Date of this Version

Spring 5-5-2014


Colley, 2014


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Architectural Engineering, Under the Supervision of Professor Ece Erdogmus. Lincoln, Nebraska: May, 2014

Copyright (c) 2014 Ebrima Colley


This research project focuses on investigating the effects of synthetic fibers (PET) and amount of cement stabilization on the water absorption, water surface erosion, and wet compressive strength of the compressed stabilized earth blocks (CSEB). The use of locally available soils blended with fibers and cement was investigated to obtain a design mix for compressed stabilized earth blocks capable of staying intact in wet and humid regions in the world (i.e. regions with annual rainfall of over 50 in). Blocks with varying cement percentages of 5, 8, 10, and 15% by weight were produced with 3 specimens each, with and without fiber at 0.25% by weight of the dry material (17 lb).

The findings of the research indicate that PET fibers increase the water absorption rate of CSEBs. The absorption rate of fiber reinforced blocks with 5 and 8% cement content was 2% more than the unreinforced blocks. An increase in cement content increases the resistance to water surface erosion, where 8, 10, and 15% cement content had zero surface erosion for both sets of blocks. According to the results of this research, the inclusion of fibers together with the increase in cement content improves the compressive strength of CSEBs. Ten percent stabilized CSEB with 0.25% PET fibers recorded a wet compressive strength of 1082 psi, which is almost double the corresponding 10% stabilized blocks without fibers at 547 psi. However, this finding is different than common observation of fiber reinforced cementitious mixtures with respect to compressive tests. Future research is necessary to identify the causes and consistency of the strength increased observed. Based on the findings of this research, it can be concluded that 10% cement stabilized CSEB without fibers can be a viable option for water prone areas.

Adviser: Ece Erdogmus