Ramesh C Joshi

The University of Calgary · Department of Civil Engineering

A model to predict the hydraulic conductivity of consolidated clay, simulating clay liners compacted wet of optimum, is presented. The concept that clays exist as clusters and the electrical double layer theory are used to predict the hydraulic conductivity of clays for permeants of known composition. The model relates the physical properties of cl...

It has been assumed that cement – fly ash systems only work efficiently given full curing; low temperatures and (or) moisture loss may lead to poor (slow) strenght development and concomitant reduced freezing and thawing cycling and scaling performance.The aim of the present study, undertaken by the Calgary Fly Ash Research Group, was to examine th...

Results are presented from an investigation on the compressive strength and durability of concretes containing substitute materials at a 50% replacement level (by mass) of Portland cement. Seven fly ashes (sub-bituminous, bituminous, and lignitic), together with limestone and an inert material (silica flour), were used as replacement materials. Dur...

Instrumented model piles were loaded to failure using slow-maintained-load, quick-maintained-load, and constant-rate-of-penetration methods of loading. The piles were driven in a prepared dry-sand bed. The applied load, point load, and shaft resistance were measured using load cells and strain gauges, and axial force distribution was determined. Te...

Results of a field study in which vibrations due to pile driving were monitored are presented. The objective of this study was to determine the effects of pile driving on a buried gas pipeline. It was concluded that, at this site, the vibrations produced through pile driving were not significant enough to cause damage to the pipeline at distances g...

Constant strain-rate (0.01/s) uniaxial compression-strength tests were conducted on more than 200 saturated samples of six fine-grained frozen soils at temperatures between −5 and −17 °C. Saturated soil samples containing total water contents between 15% and 105% were prepared using a consolidation apparatus specially designed for this purpose. The...

The preliminary results of a study using mercury-intrusion porosimetry on freeze-dried samples of clayey soils are presented. The amount of secondary consolidation has been varied for several samples of three soil types by holding the consolidation stress steady at 120 kPa for different durations. Examination of the pore size distribution curves re...

Uniaxial compressive creep tests were conducted on saturated samples of six fine-grained frozen soils. The creep behavior of the soils with respect to variation in the creep stress, temperature, and total water content is examined. The test results indicate existence of a unique relationship between the secondary creep rate, , and the time to the o...

Model piles were tested in dry uniform sand to study the effect of loading history on the behaviour of piles in compression and tension. A sand bed was prepared by the raining technique, and a smooth cylindrical instrumented pile was driven into the sand. Load tests on piles were conducted at a constant rate of penetration of 0.5 mm/min. The effect...

The main objective of this study was to understand the effect of aging on the penetration resistance of freshly deposited sands. Two types of sand, locally available river sand used as masonry sand and Beaufort Sea sand, were selected for the study. The sands were allowed to age under a constant stress of 100 kPa in a specially designed apparatus i...

This paper presents the results of an experimental investigation into usage of Fenton's reagent (a mixture of ferrous salts and hydrogen peroxide) to remediate diesel-impacted soils. A number of process variables such as the presence of iron salts, comparison between ferrous and ferric salts, amount of diesel washed out and mineralized and the use...

This paper presents the results of a laboratory investigation on hydraulic conductivity (k, also known as coefficient of permeability), compressive strength, and contaminant leachability of self-cementitious fly ash produced by two different coal-fired thermal power plants in Alberta. Hydraulic conductivity data are presented for fly ash and lime-m...

The upstream oil and gas industry has used flare pits (FPs) for decades to store and/or burn produced fluids generated at well sites, compressor stations, and batteries. Since produced fluids contain liquid hydrocarbons, process chemicals, crude bitumen, or salt water, FPs usually contain high levels of hydrocarbons, metals, and salts. At present,...

The electrolytic processes in the ASTM C 1202 chloride penetration test method have been reexamined both theoretically and experimentally. The analyses show that hydroxyl (OH-) ion generated at the cathode during testing carries a substantial part of the current and that chloride (Cl-) ion is not the sole current carrier. Attention has also been dr...

Results from a comprehensive experimental program conducted to examine the feasibility of constructing landfill liners or vertical barriers to pollutant migration at contaminated sites using fly ash based materials are described. The materials evaluated are fly ash, lime‐fly ash, poly vinyl alcohol (PVA) polymer‐lime‐fly ash and bentonite‐fly ash....

The applicability of an equation that suggests the effective diffusion coefficient of ions through a charged porous medium is linearly related to the square root of the concentration of ions is evaluated. Data from experiments on diffusion of NaCl and LiCl solutions through Na and Li bentonites were analyzed using the proposed equation. Plots of ef...

Thermal treatment alters the physical and mechanical properties of clayey soils. Thermally treated soils have been used since primitive times for making trails for access and bricks for dwellings. In comparison with other soil-improvement methods, thermal stabilization produces immediate results. Thermal treatment of clays alters several material c...

An approximate, semi-theoretical method to determine the complete consolidation curve of undisturbed sensitive soils from index properties and in situ undrained shear strength is presented. The consolidation curve for the soft sensitive soils consists of three distinct zones. In order of increasing stress, these zones are described as cemented, tra...

Creep tests were conducted on a fine-grained frozen soil at different salinities ranging from 0 to 20 ppt (parts per thousand), at temperatures between −5 °C and −17 °C and at two total water contents of around 34% and 52%. The test results indicated that the presence of salinity in the pore water considerably increases the creep strain rates of th...

In this study, the effect of replacing calcined gypsum in wallboards with fly ash was studied. Three types of fly ash produced in Alberta, Canada, were used for replacement of as much as 40% of the calcined gypsum in wallboards. All the three types of fly ash were pozzolanic as well as self-cementitious. Wallboard specimens were prepared in the lab...

Constant strain-rate and creep tests were conducted in uniaxial compression on saturated samples of six fine-grained frozen soils at temperatures between −5 ° and −17 °C. From the test results, a number of relationships were developed that do not include temperature as an explicit parameter. The constant strain-rate test results yielded relationshi...

Increase in strength with time due to primary consolidation and aging, is well recognized in fine grained soils. No time dependent effects are normally considered to occur in the case of granular soils as these soils are very pervious and are primarily composed of inert minerals such as quartz and feldspar. Of late, however, there have been some re...

Uniaxial compressive creep tests were conducted on saturated samples of six fine-grained frozen soils. The creep behavior of the soils with respect to variation in the creep stress, temperature, and total water content is examined. A method of analysis is presented whereby the creep behavior of a fine-grained frozen soil at various stresses, temper...

A simple method to optimize the level of cement replacement by fly ash in cement-fly-ash mortar and concrete is proposed. The method is based on flow-table tests. In this test, for any specific level of flow a decrease in water content of the mix increases the number of drops. The lines representing water content of the mixes and the logarithm of t...

There have been only a few direct investigations of clay compression at the microlevel. This Note presents the preliminary results of an investigation of the microstructural changes due to consolidation of four clays, each stressed to four levels in one-dimensional consolidation, freeze-dried and analysed using mercury intrusion porosimetry.

Constant strain rate uniaxial compressive strength tests were conducted on saturated samples of six fine- grained frozen soils. The post peak compressive strength behavior of the frozen soils with respect to the variation in total water content, dry unit weight and the temperature conditions are studied. Test results indicated a ductile type of def...

Sensitive soils, in general, are prone to mechanical disturbances while sampling, handling, and testing. This necessitates the prediction of true field behavior. The compressibility response of such soils is typical of having three zones, mechanistically explained as nonparticulate, transitional, and particulate. Such zoning has enabled the develop...

A comprehensive laboratory investigation was conducted to examine the compressive response of stiff cemented clays subjected to cement removal under stress. Results indicate that removal of cementation bonds in a stressed, stiff, cemented clay can cause a increase in soil volume, with the void ration increasing to the level of equilibrium for the u...

The note describes the application of the generalized compressibility equations for normally and overconsolidated clays (presented by Nagraj & Srinivasa Murthy, 1986) based on physico-chemical principles. The ideas are used in a new combination as a method of identifying possible particle cementation in overconsolidation clays. Examination of the p...

For highly compressible normally consolidated saturated soil the compression index, C//c, is not constant over the entire pressure range. However, the ratio of the compression index and the initial specific volume, generally known as the compression ratio, appears to be constant. Thus settlement seems to depend on C//c/(1 plus e) rather than C//c a...

The development and initial testing of an erosion test apparatus for soil cement mixtures is described. The device differs from other test apparatuses in that it combines the impacting forces of waves and debris. The apparatus consists of a water jet that impacts the sample causing erosion and also a number of small stones that are activated by the...

An experimental programme was undertaken to determine whether Canadian fly ash, and in particular Western-Canadian fly ash, can be used to replace clay as the main ingredient in brick-masonry units. These preliminary examinations show that Western-Canadian fly ash as the solid material, combined with an adequate binder, can be used to produce a sup...

Raymond E. Davis and his associates appear to have coined the term “fly ash” in 1937. Following the pioneering studies by the U.S. Bureau of Reclamation for the Hungry Horse Dam, the use of fly ash for massive hydroelectric structures increased rapidly in the U.S., with ASTM issuing the first standard in 1954. In 1982, Canada issued a National Stan...

An increased acceptance of the use of fly ash in concrete requires adequate demonstration that such concrete will be durable. The most important factor which determines durability of a concrete to aggressive agents is its permeability. This paper outlines methods which are being employed to measure the permeability of plain and fly ash concretes to...

There has been a concerted effort over the last few years in Alberta to increase our level of understanding of hydrogen peroxide (H2O2) technology as an oxidation remediation technique for hydrocarbon-contaminated sites. H2O2 (and Fenton's reagent - a mixture of H2O2 and iron salts) oxidizes contaminant hydrocarbons, and it degrades and releases ox...