Study of compressive strength evolution in soil cement samples with fly-ash admixtures

Abstract

Improving a soil is a process of increasing its physical/mechanical properties without changing its natural structure. Improvement is reached by means of the knitted materials, or other methods when strong connection between soil particles is established. The main reason of designing cement-soil columns is to improve properties of local soils (such as strength and stiffness) by mixing them with various cementing materials. Cement and calcium are the most commonly used binders. However, new research undertaken worldwide proves that apart from these materials, also gypsum or fly ashes can also be successfully implemented. As the Deep Soil Mixing is still being under development, anticipating mechanical properties of columns in particular soils and the usage of cementing materials in formed columns is very difficult and often inappropriate to predict. That is why a research is carried out in order to find out what binders and mixing technology should be used. The paper presents several results of the testing procedures related to soil-cement quality and internal capacity of Deep Soil Mixing columns. Presented results concerning capacity testing of laboratory samples and laboratory procedures on various categories of samples were picked from R&D and consulting works offered by Wroclaw University of Science and Technology (WrUST). The work contains two independent groups of analyses. The first one comprises results coming from the previous laboratory research undertaken at the University. This is just a small part of huge investigation which is aimed at boosting the knowledge of possible implementation of fly ashes into the DSM columns. The second part contains results of specimen prepared by the author for the purpose of MSc Diploma Work.