Shrinkage Characteristics of Cement Stabilized Rammed Earth

Abstract

The introduction of stabilization techniques to earth construction has seen its immergence as a good alternative walling material in the recent times. Further popularisation of earth construction has resulted due to the increased awareness on sustainable construction. Research and development work was carried out on stabilized rammed earth technology with several soil types available in Sri Lanka. It was found that gravelly and sandy lateritic soils which are commonly available in many parts of the country are the best suited for stabilization with well accepted chemical stabilizer; cement. Several studies have been carried out to determine the optimum cement content, compressive strength with different soil types and flexural strength of stabilized rammed earth. All these studies have shown that stabilized rammed earth is a desirable material for single storey construction with possible extension to two storey load bearing construction. Rammed earth offers an alternative, which could reduce the skilled labour requirement. One of the systems devised in Sri Lanka recently was a combination of cement stabilized earth blocks as corner columns and rammed earth walls in between them. However, the shrinkage of the wall panels should be carefully attended since excessive shrinkage can lead to wide cracks between the cement stabilized soil columns and the rammed earth walls. Thus, studies into the shrinkage characteristics of different composition of soils will be very useful. It is also useful to determine the effects of curing on the shrinkage characteristics. Three different commonly available lateritic soils were used in the experimental programme to measure shrinkage strains. It was found that gravelly laterite soil gives the minimum shrinkage strain. The main findings of this paper have been used to propose solutions that can be used to minimise the cracks occurring due to shrinkage of walls constructed with rammed earth.