Optimization of Soil Stabilization with Class C Fly Ash


Book Description

Previous Iowa DOT sponsored research has shown that some Class C fly ashes are ementitious (because calcium is combined as calcium aluminates) while other Class C ashes containing similar amounts of elemental calcium are not (1). Fly ashes from modern power plants in Iowa contain significant amounts of calcium in their glassy phases, regardless of their cementitious properties. The present research was based on these findings and on the hyphothesis that: attack of the amorphous phase of high calcium fly ash could be initiated with trace additives, thus making calcium available for formation of useful calcium-silicate cements. Phase I research was devoted to finding potential additives through a screening process; the likely chemicals were tested with fly ashes representative of the cementitious and non-cementitious ashes available in the state. Ammonium phosphate, a fertilizer, was found to produce 3,600 psi cement with cementitious Neal #4 fly ash; this strength is roughly equivalent to that of portland cement, but at about one-third the cost. Neal #2 fly ash, a slightly cementitious Class C, was found to respond best with ammonium nitrate; through the additive, a near-zero strength material was transformed into a 1,200 psi cement. The second research phase was directed to optimimizing trace additive concentrations, defining the behavior of the resulting cements, evaluating more comprehensively the fly ashes available in Iowa, and explaining the cement formation mechanisms of the most promising trace additives. X-ray diffraction data demonstrate that both amorphous and crystalline hydrates of chemically enhanced fly ash differ from those of unaltered fly ash hydrates. Calciumaluminum- silicate hydrates were formed, rather than the expected (and hypothesized) calcium-silicate hydrates. These new reaction products explain the observed strength enhancement. The final phase concentrated on laboratory application of the chemically-enhanced fly ash cements to road base stabilization. Emphasis was placed on use of marginal aggregates, such as limestone crusher fines and unprocessed blow sand. The nature of the chemically modified fly ash cements led to an evaluation of fine grained soil stabilization where a wide range of materials, defined by plasticity index, could be stabilized. Parameters used for evaluation included strength, compaction requirements, set time, and frost resistance.




Soft Soil Engineering


Book Description

Soft soils present particular challenges to engineers and an understanding of the specific characteristics of these soils is indispensable. Laboratory techniques such as numerical modelling, theoretical analysis and constitutive modelling give new insights into soft soil material behaviour, while large-scale testing in the field provides important information in areas such as slope stability and soft soil improvements. This collection of papers from the Fourth International Conference on Soft Soil Engineering, Vancouver, 2006, presents an international appraisal of current research and new advances in engineering practices, illustrating the theory with relevant case studies. Geotechnical professionals, engineers, academics and researchers working in the areas of soft ground engineering and soft soil engineering will find this a valuable book.




Handbook of Fly Ash


Book Description

The drive to develop more sustainable materials has made fly ash a valuable raw material in many different applications. Comprehensive and authoritative, Handbook of Fly Ash highlights the latest research efforts to develop the properties of fly ash to maximum utility while safeguarding the environment. This book takes an interdisciplinary approach to the research into the classification and compositions of various types of fly ash, such as bottom ash and boiler slag, special classes of fly ash, and their sources around the globe. This is followed by a discussion of fly ash-reinforced composites, such as elastomer-based composites and metal matrix composites. This book also covers a wide range of applications of fly ash in cement, concrete, bricks and blocks, road construction, wastewater treatment, and scrubber sludge solidification. - Highlights the recent developments in the utilization of fly ash including its preparation, functionalization, properties, and handling. - Places a focus on a wide variety of fly ash applications including recent innovations, such as alkali-activated binder, polypropylene composite, and geopolymer concrete. - Includes comprehensive coverage of the characteristics of fly ash with a particular focus on health hazards if it is not properly disposed. - Discusses fly ash-reinforced composites, such as polymer/elastomer-based composites and metal matrix composites.




Proceedings of 5th International Conference on Civil Engineering and Architecture


Book Description

This book states that the proceedings gathers selected papers from 2022 5th International Conference on Civil Engineering and Architecture (ICCEA 2022), which was held in Hanoi, Vietnam on December 16-18, 2022. The conference is the premier forum for the presentation of new advances and research results in the fields of theoretical, experimental, and practical civil engineering and architecture. And this proceedings from the conference mainly discusses architectural design and project management, environmental protection and spatial planning, design and analysis of building materials, and structural engineering and safety. And these materials can be useful and valuable sources for researchers and professionals working in the field of civil engineering and architecture.










Proceedings of the 8th International Congress on Environmental Geotechnics Volume 1


Book Description

This book gathers selected papers presented at the 8th International Congress on Environmental Geotechnics (ICEG), held on October 28 - November 1, 2018 in Hangzhou, China. The theme of the congress is “Towards a Sustainable Geoenvironment”, which means meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Under this theme, the congress covers a broad range of topics and provides an excellent opportunity for academics, engineers, scientists, government officials, regulators, and planners to present, discuss and exchange notes on the latest advances and developments in the research and application of environmental geotechnics.




Monthly Checklist of State Publications


Book Description

June and Dec. issues contain listings of periodicals.




Iowa Documents


Book Description




HRIS Abstracts


Book Description