S. VIJAYA BHASKAR(1) and K. NAGENDRA PRASAD(2)

(1) Academic Consultant, Department of Civil Engineering, S.V.University, Tirupati 517 502, Andhra Pradesh, India. E-mail: svijayabhaskar104@gmail.com (2) Professor of Civil Engineering, S.V.University , Tirupati 517 502,Andhra Pradesh, India. E-mail: kotanp_svu@yahoo.com

ABSTRACT
Stabilized earth is a substitute building material which is considerably cheaper than using conventional brick and cement mortar, and is also environmentally sustainable. Direct use of earth without cementitious compounds may not be feasible owing to low mechanical response, significant volume change characteristics and inadequate resistance to weathering. The present experimental investigation considers clayey soils from eight different locations of the Tirupati Region. The fine fraction ranges from 37-89%, the Liquid Limit values from 20-70% and the Plasticity Index from 7-50%. Ordinary Portland cement is used in conjunction with the soils in proportions of 3%, 5% and 10% based on earlier findings that 3% is usually effective and proportions over 10% may not prove to be economical and practical. The present study investigates the compressive strength of cement-stabilized earth in the form of cylindrical specimens prepared at their maximum dry densities. The compressive strength of the specimens was observed under uniaxial compression. The relationship between ageing the material at constant temperature and moisture conditions was examined and a simple hyperbolic relationship has been identified. The predicted compressive strength of specimens determined using the method proposed was compared with experimental results and found to be in good agreement. The hyperbolic approach suggested is very simple and useful for practicing engineers to assess the proportion of cement required with respect to strength development for practical use in different engineering applications.
(Key words: Locally available materials, sustainability, cement stabilized earth blocks, compressive strength, prediction by hyperbolic modelling)ABSTRACT
Stabilized earth is a substitute building material which is considerably cheaper than using conventional brick and cement mortar, and is also environmentally sustainable. Direct use of earth without cementitious compounds may not be feasible owing to low mechanical response, significant volume change characteristics and inadequate resistance to weathering. The present experimental investigation considers clayey soils from eight different locations of the Tirupati Region. The fine fraction ranges from 37-89%, the Liquid Limit values from 20-70% and the Plasticity Index from 7-50%. Ordinary Portland cement is used in conjunction with the soils in proportions of 3%, 5% and 10% based on earlier findings that 3% is usually effective and proportions over 10% may not prove to be economical and practical. The present study investigates the compressive strength of cement-stabilized earth in the form of cylindrical specimens prepared at their maximum dry densities. The compressive strength of the specimens was observed under uniaxial compression. The relationship between ageing the material at constant temperature and moisture conditions was examined and a simple hyperbolic relationship has been identified. The predicted compressive strength of specimens determined using the method proposed was compared with experimental results and found to be in good agreement. The hyperbolic approach suggested is very simple and useful for practicing engineers to assess the proportion of cement required with respect to strength development for practical use in different engineering applications.

KEYWORDS: Locally available materials, sustainability, cement stabilized earth blocks, compressive strength, prediction by hyperbolic modelling)