Lime stabilization of clay minerals and soils

This paper examines the relationship between the microstructure and engineering properties of cement-treated marine clay. The microstructure was investigated using x-ray diffraction, scanning electron microscopy, pH measurement, mercury intrusion porosimetry, and laser diffractometric measurement of the particle size distribution. The engineering properties that were measured include the water content, void ratio, Atterberg limit, permeability, and unconfined compressive strength. The results indicate that the multitude of changes in the properties and behavior of cement-treated marine clay can be explained by interaction of four underlying microstructural mechanisms. These mechanisms are the production of hydrated lime by the hydration reaction which causes flocculation of the illite clay particles, preferential attack of the calcium ions on kaolinite rather than on illite in the pozzolanic reaction, surface deposition and shallow infilling by cementitious products on clay clusters, as well as the presence of water trapped within the clay clusters.

Physicochemical and engineering behavior of cement treated clays

http://cec.sut.ac.th/download/published/CBM-micro.pdf

Analysis of strength development in cement-stabilized silty clay from microstructural considerations

THE USE OF HYDRATED LIME, CA/OH/2, FOR MODIFYING, UPGRADING, AND STABILIZING SOILS IS INCREASING GREATLY. THIS MEANS HIGHWAY LABORATORIES HAVE HAD THEIR WORK LOADS INCREASED, AND IN MANY INSTANCES, MORE THAN DOUBLED FOR A PARTICULAR JOB. BEFORE THE ADVENT OF THE USE OF LIME, THE LABORATORY WAS FINISHED WITH TESTING WHEN A SOIL WAS CLASSIFIED AS UNSUITABLE. NOW THE SAME SOIL IS TESTED AND RETESTED TO FIND THE PERCENTAGE OF LIME REQUIRED TO BRING THE SOIL WITHIN SPECIFICATIONS. IN MOST CASES THE PERCENTAGE IS DETERMINED BY COMPRESSIVE TESTS, ATTERBERG LIMITS TESTS, OR BOTH. THE REACTION OF LIME AND SOIL CAN BE DESCRIBED AS A SERIES OF CHEMICAL REACTIONS. THE RESULTS OF THESE REACTIONS ARE EXPRESSED AS A CHANGE IN THE PLASTICITY, SWELL, SHRINKAGE OR COMPRESSIVE STRENGTH OF THE SOIL. THEREFORE, A QUICK OR SIMPLE TEST IS NEEDED TO SHOW THE AMOUNT OF LIME REQUIRED TO REACT CHEMICALLY WITH A SOIL TO BRING ABOUT THESE PHYSICAL CHANGES TO AN OPTIMUM DEGREE. LABORATORY TESTS, INVOLVING MINERALOGICAL, PHYSICAL AND CHEMICAL CHARACTERISTICS OF UNTREATED AND LIME-TREATED SOILS HAVE PROVEN THAT PH TESTS CAN BE USED TO DETERMINE THE OPTIMUM LIME REQUIREMENTS OF A SOIL. /AUTHOR/

A quick test to determine lime requirements for lime stabilization

THE USE OF HYDRATED LIME HAS BEEN GROWING IN THE FIELD OF SOIL STABILIZATION ALTHOUGH IT HAS BEEN USED FROM COAST TO COAST IN THE UNITED STATES AND BY SOME NATIONS ABROAD, THE REACTION OF HYDRATED LIME WITH THE SOIL IS STILL A MYSTERY, PARTICULARLY WITH RESPECT TO ITS RELATIVE EFFECTIVENESS AND RATES OF REACTION WITH VARIOUS SOILS A RESEARCH PROJECT TO DETERMINE THE REACTION OF HYDRATED LIME AND SOIL IS UNDER WAY AT THE UNIVERSITY OF ILLINOIS BECAUSE OF THE COMPLEXITY OF SOILS AND BECAUSE LIME IS OF GREATER BENEFIT TO A HEAVY CLAY SOIL, THE FIRST PART OF THE INVESTIGATION HAS BEEN DEVOTED TO A STUDY OF THE EFFECTS OF HYDRATED LIME ON PURE CLAY MINERALS BY THE AID OF X-RAY DIFFRACTION AND DIFFERENTIAL THERMAL ANALYSIS, IT HAS BEEN POSSIBLE TO WATCH AND IDENTIFY THE REACTIONS WHICH TAKE PLACE THE FIRST REACTION, WHICH IS BROUGHT ABOUT IMMEDIATELY WHEN LIME IS ADDED, IS REPLACEMENT OF ABSORBED IONS BY CALCIUM IONS, THE SECOND, FORMATION OF A SERIES OF NEW MINERALS, THE THIRD, CARBONATION OF THE HYDRATED LIME THESE REACTIONS, ILLUSTRATED BY TYPICAL X-RAY EXAMPLES, OFFER DEFINITE PROOF AS TO WHY DIFFERENT RATES OF REACTION OCCUR WITH DIFFERENT SOILS /AUTHOR/

Reaction of hydrated lime with pure clay minerals in soil stabilization

IN THE FALL OF 1956 AND THE SPRING OF 1957 SUBGRADE SOILS ON THREE PROJECTS IN VIRGINIA WERE STABILIZED WITH HYDRATED LIME. THE PROJECTS, LOCATED APPROXIMATELY 150 MILES APART, WERE CONSTRUCTED ON THREE DIFFERENT SOIL TYPES. THE CLAY FRACTION OF EACH OF THE THREE SOILS WAS COMPOSED OF DIFFERENT CLAY MINERALS. THEREFORE, THERE WAS A CONSIDERABLE DIFFERENCE IN THE PHYSICAL PROPERTIES OF THE SOILS. THE THREE PROJECTS WERE SAMPLED DURING 1960 FOR THE PURPOSE OF STUDYING THE EFFECTS OF ADDITION OF HYDRATED LIME. X-RAY DIFFRACTION DATA OF THE TREATED SOILS REVEALED THAT NEW MINERALS--CALCIUM SILICATE-HYDRATES AND CALCIUM CARBONATE-- HAD BEEN FORMED. PETROGRAPHIC ANALYSIS OF THIN SECTIONS PREPARED FROM THE TREATED SOILS SHOWED THAT THE SOURCE OF ADDITIONAL STRENGTH WAS A CEMENTING MATERIAL, HYDRATED CALCIUM SILICATES, WHICH NOW INTERLACES THE SOIL GRAINS. /AUTHOR/

Ralph E Grim

Papers

A quick test to determine lime requirements for lime stabilization

Reaction of hydrated lime with pure clay minerals in soil stabilization

Formation of new minerals with lime stabilization as proven by field experiments in virginia