Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF) steelmaking, electric-arc-furnace (EAF) steelmaking, and ladlefurnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace-ladle [EAF(L)] slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM) studies. The XRD patterns of both BOF and EAF(L) slag samples were very complex, with several overlapping peaks resulting from the many minerals present in these samples. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L) slag samples. SEM micrographs showed that the majority of the sand-size steel slag particles had subangular to angular shapes. Very rough surface textures with distinct crystal structures were observed on the sandsize particles of BOF and EAF(L) slag samples under SEM. The characteristics of the steel slag samples considered in this study are discussed in the context of a detailed review of steel slag properties.

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Chemical, mineralogical, and morphological properties of steel slag

Steel slag in China: Treatment, recycling, and management.

Abstraet-A knowledge of the distribution of pore sizes in clay and soil bodies is a useful element in the microstructural characterization of such materials. Pore-size distributions and total porosity of a number of reference clays, naturally-occurring subsoils, and commercial clay samples prepared in various ways were determined by mercury porosimetry. The range of equivalent pore diameter explored covered almost five orders of magnitude, from several hundred microns down to approximately 150A. The method and its assumptions are critically evaluated, and measurements of the contact angle of mercury on clays yield values of 139 ~ for montmorillonite and 147 ~ for kaolinite and illite clays. The extent of shrinkage on oven-drying prior to mercury intrusion is assessed in each case and found to vary from insignificant to as much as 30 per cent of the pore space, depending on microstructural state and degree of initial saturation. The development of techniques for water removal which do not involve change in pore structure is explored. Some preliminary results for structurally weak saturated clays suggest that critical-region drying and perhaps freeze-drying procedures may be practical.

Pore Size Distributions in Clays

This is the first of a series of reports on sound velocity, elasticity, and related properties of marine sediments from sedimentary environments associated with three major physiographic provinces in the North Pacific and adjacent areas: the continental terrace (shelf and slope), the deep-water abyssal plain (turbidite), and the abyssal hill (pelagic). The following properties are listed in tables and illustrated in diagrams that interrelate various properties: grain size (mean diameter, percentages of sand, silt, and clay), bulk density, density of mineral grains, porosity, sound velocity, velocity ratio (velocity in sediment/velocity in sea water), impedance, and density × (velocity)2. Values are given for each sediment type within each environment. Significant differences in the density and porosity of the environments studied are caused by mineralogy, size and shape of grains, and sediment structure; presence of diatoms and clay mineralogy are particularly important. General equations and diagrams relating density and porosity to velocity should be abandoned in favor of entry into diagrams or equations for a single environment; velocity is then predictable within 1 to 2 per cent in most environments. Mean grain size has one of the best empirical relationships with velocity, which permits derivation of useful data from size analyses of dried cores. Porosity and density are excellent indices by which to determine values of impedance and density × (velocity)2. There is no usable, empirical relationship between sound velocity and shear strength (cohesion) as measured in soil mechanics tests. No anisotropic velocity relationships were measured in surficial sediments, and none is predicted for the upper few hundred meters in sea-floor sediments.

Sound velocity and related properties of marine sediments, North Pacific

The time-dependent behavior of soils has been investigated extensively through one-dimensional and triaxial test conditions. Most of the observations in literature have focused on the determination of the time-dependent behavior of clayey soils, whereas the reported experimental studies of granular materials are few. This paper presents an up-to-date review of the various observed time- and rate-dependent phenomena that are known to exist for both clay and sand. The description is carried out separately for creep, stress relaxation, rate dependency, and structuration in laboratory experiments. All of the above-mentioned phenomena are present in both sand and clay. The time-dependent phenomena are more pronounced in clay than sand. However, sand exhibits relatively large deformations at high confining pressures because of grain crushing. Furthermore, the review revealed an essential characteristic situation for soils. That is whether the time-dependent behavior can be characterized as isotach or nonisotach...

Evaluation of Time-Dependent Behavior of Soils

To create significant pore water pressure in a tiny test specimen of clay, it must be loaded with large increments. This causes the specimen to compress at rates to several million times the rate for an equivalent element of soil in the field. A laboratory investigation of compression rates, under incremental and continuous loading, showed that the compressibility of an undisturbed sensitive clay was greatly influenced by the rate of compression. These rapid tests gave pressure-compression curves similar to those for identical specimens, and demonstrated that the relative contributions of primary and secondary consolidation is a function of test procedure. When compared with long duration incremental loading tests, however, they revealed a much higher preconsolidation pressure and less compressibility. It was therefore concluded that the influence of compression rate may be important in the interpretation of consolidation tests and warrants more attention and research.

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Interpretation of the consolidation test

Quick clays of eastern canada

The consolidation characteristics of natural soils vary widely depending on their stress history, void ratio, and structure. The standard method of measuring consolidation properties involves the incremental loading of specimens of soil, but other methods using controlled loading techniques have been useful in improving the understanding of soil compressibility. The various test methods and their influence on the evaluation of consolidation properties are reviewed in the paper. The interpretation of preconsolidation pressure for some soils is greatly influenced by the rate of loading. Total consolidation settlements can be estimated reasonably well from good oedometer tests, but predictions of the rate of settlement are usually quite unreliable in the primary consolidation stage. The ability to evaluate and interpret consolidation tests has been improved where the tests have been carried out in conjunction with field observations. More research of this kind is needed to improve the usefulness of consolidation theories and testing.

State of the art: Evaluation and interpretation of soil consolidation tests

Expanding steel slage backfill was unexpectedly found to be the cause of vertical movements of the floor of a basementless building that resulted in significant damage to window and door frames. Five years after construction some parts of the building were still heaving at a rate of 1 cm per yr. Swelling properties of the slag when exposed to different conditions of temperature and humidity are reported. Characteristics of iron blast furnace and steel open hearth furnace slags are described and on this basis it is advocated that only blast furnace slags be used in cases where long-term volume changes cannot be tolerated. Use of other slags in such circumstances should be prohibited unless accompanied by specific evidence that they will not expand.

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Building Damage from Expansive Steel Slag Backfill

FAILURES OF NATURAL SLOPES IN SENSITIVE CLAYS OFTEN RETROGRESS LEAVING A CHARACTERISTIC CRATER WHICH IS WIDER THAN THE OPENING IN THE SLOPE. TWO ACTUAL FAILURES OF THIS TYPE THAT OCCURRED NEAR OTTAWA, CANADA ARE DESCRIBED AND COMPARED WITH STABLE SLOPES IN THE SAME GENERAL AREA. ONE OF THE FAILURES OCCURRED SEVERAL HUNDRED YEARS AGO BUT CHANGES IN GROUND WATER CONDITIONS SINCE FAILURE APPEAR TO HAVE INCREASED THE STABILITY OF ADJACENT SLOPES IN THAT AREA. THE SECOND FAILURE, IN AN AREA OF ACTIVE SLIDING, OCCURRED IN 1963. IN EACH CASE THE REQUIRED STRENGTH FOR STABILITY UNDER VARIOUS GROUND WATER CONDITIONS HAS BEEN COMPUTED AND COMPARED WITH MEASURED VALUES. IT IS CONCLUDED THAT AN EFFECTIVE STRESS ANALYSIS OF THESE SLOPES YIELDS SATISFACTORY RESULTS IF TESTS ARE CONDUCTED IN THE WORKING STRESS RANGE AND GROUND WATER CONDITIONS ARE CAREFULLY MEASURED. /ASCE/

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Carl B. Crawford

Papers

Interpretation of the consolidation test

Quick clays of eastern canada

State of the art: Evaluation and interpretation of soil consolidation tests

Building Damage from Expansive Steel Slag Backfill

Stability of natural slopes in sensitive clay