Non-destructive evaluation of cement-based materials from pressure-stimulated electrical emission - Preliminary results

This is the post-print version of the final paper published in Construction and Building Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.This paper introduces the possibility of in situ assessment of loading and remaining strength in concrete structures by means of measuring discharge of electric current from loaded specimens. The paper demonstrates that the techniques have been applied to other rock-like materials, but that for the first time they are applied to cement-based materials and a theoretical model is proposed in relation to the appearance of electrical signals during sample loading and up to fracture. A series of laboratory experiments on cement mortar specimens in simple uniaxial compression, and subsequently in bending – hence displaying both tension and compression – are described and show clear correlations between resulting strains and currents measured. Under uniaxial loading there is a well-defined relationship between the pressure-stimulated current (PSC) as a result of a monotonic mechanical loading regime. Similar results are observed in the three-point bending tests where a range of loading regimes is studied, including stepped changes in loading. While currents can be measured at low strains, best results seem to be obtained when strains approach and exceed yield stress values. This technique clearly has immense potential for structural health monitoring of cement-based structures. Both intermittent and continuous monitoring becomes possible, and given an ongoing campaign of monitoring, remaining strength can be estimated

Engineering at Gettysburg College

This little volume narrates the story of engineering instruction at Gettysburg College, particularly of the Engineering Department that functioned from 1912 to 1940. It includes also an account of the apparently first venture in engineering by an American liberal arts college, undertaken during the brief association of the renowned Herman Haupt with Gettysburg College between 1837 and 1847. Time dims our memories. Although there are more than fifty living alumni who were graduated from the Engineering Department, many Gettysburgians are unaware of its existence and accomplishments. The purpose of this story is to place on record a significant aspect of our tradition. [excerpt]https://cupola.gettysburg.edu/collegehistory/1000/thumbnail.jp

The origins of American industrial success: Evidence from the US portland cement industry

The contributions of innovations, factor endowments and institutions to American industrialization are examined through analysing the rise of the American portland cement industry. Minerals abundance contributed in multiple ways to the spectacular rise of the industry from the 1890s. However, the results of a structural econometric analysis of entry suggests geological surveys, institutions highlighted by David and Wright, played a contributing rather than critical role in the American portland cement industry overcoming incumbent European portland cement and American natural cement producers.American Economic History; Empirical Industrial Organization; Portland Cement

Cement testing

For a Thesis in 1898 I did some work on cement testing with very satisfactory results, but I did but little more than get a few ideas as to how to conduct the experiments to best advantage. For the present year I have taken up the work for further investigation --page 1

Geopolymer Concrete Production by Activating Alkaline With Silica Sand, Blast Furnace Slag and Fly Ash

In this paper, it was aimed to manufacture a functional geopolymer structure by activating silica sand, fly ash disposed from Afsin-Elbistan Thermal Power Plant and blast furnace slag obtained from Iskenderun Ferrous & Steel Plant with NaOH. Concrete mortars containing alkaline-activated aggregates were shaped in 4 cm x 4 cm x 16 cm and 10 cm x 10cm x 10 cm molds. These samples were kept in oven at 75 oC during 20 hours. Bending resistance, specific weight, thermal conductivity coefficient, compressive strength and ultrasound transmission rate of each sample were measured

Dynamic Compression Plating with Strategic Screw Fixation in Diaphyseal Transverse Fractures of the Radius: the Biomechanical Effect of Numbers of Screws

Introduction.Diaphyseal fracture of radius could compromise function unless adequately treated. Open reduction and internal fixation with six cortices of screw fixation on either side of the fracture is generally accepted as the best method of treatment. Unfortunately, a very high rate of refracture after plate removal has been observed for as high as up to 22%. Although a number of factors are thought to be the cause of such a high rate, such as the type of plate used, time from plating to plate removal, quality of reduction and compression achieved, type and duration of immobilization after plate removal, nevertheless, the stress riser from the screw holes is also considered as one of the important factor. In accordance with the stress riser from screw holes, number of screws introduced into bone played a very important role. The objective of this study is to biomechanically compare the load to failure between constructs for the treatment of diaphyseal transverse fractures of the radius in skeletally mature bone. Materials and methods. Sixteen skeletally mature human radii were retrieved, devoid of soft tissue including periosteum. Transverse osteotomy was done in each radius in its midpoint. In the control group, the radius was fixed with 6-holes 6-screws construct. In the test group, the radius was fixed with 6-holes 4-screws construct. All radii were fixed with 3.5mm mini Dynamic Compression Plates. They were then randomly divided into two groups, with each group consisted of four controls and four test specimens. Group I was tested in three-point bending force and group II was tested in axial compression force.Results.In the three-point bending test, the controls showed slightly higher load to failure but this value was not significant (p = 0.57). Meanwhile in the axial compression test, the test group showed higher load to failure with a p-value of 0.05 which was marginally significant.Conclusions.The 6-holes 6-screws construct showed higher load to failure when compared to the 6-holes 4-screws construct in terms of 3-point bending force although the value was not significant. In contrast, the 6-holes 4-screws construct showed a higher load to failure in terms of axial compression force and the value was deemed marginally significant. Furthermore, failure starting point in this experimental study was observed in the screw holes

Substitution local resources basalt stone scoria Lampung, Indonesia, as a third raw material aggregate to increase the quality of portland composite cement (PCC).

Domestic cement demand is increasing in line with the increase of development of property sector and construction sector. Cement is one of the important components in making a permanent building. The function of cement in a construction is as an adhesive material that affects the strength of a building. The process of making cement is divided into two groups, namely hydraulic cement and non-hydraulic cement. Hydraulic cement consists of Portland type cement and PCC type cement, PPC cement and slag cement. The type of PCC cement (Portland Composite Cement) is produced from grinding clinker with gypsum with the addition of third raw material. The purpose of this research is to know the effect of cement quality improvement with substitution of basalt scoria stone raw material as much as 0-10% as the third raw material. The source of basalt scoria stone originated from Lampung Timur, Indonesia. The fineness test showed cement fineness was 2983-3665 cm2/gr with minimum SNI standard 2800 cm2/gr. Residue test meets the requirements of SNI standard that is equal to 16,07% -18,55%. The compressive strength test was performed at ages 3, 7 and 28 days and obtained the result that the optimum compressive strength produced was 235, 314, 394 kg/cm2. Basalt rock usage as substitution material in cement production can decrease environmental pollution caused by clinker production. Based on the cost estimation analysis, the use of basalt stone can decrease the production cost which impact on the increase of profitN/

A commercial test of four hydraulic cements

Citation: Hanson, Gustaf William. A commercial test of four hydraulic cements. Senior thesis, Kansas State Agricultural College, 1900.Morse Department of Special CollectionsIntroduction: It was the intention of the writer to make a test of cements made only in Kansas; but being able to secure but two Kansas Cements, two other leading commercial brands were secured with which to make comparison. The cements that were put under test are as follows: Germania, a Portland cement, Iola, a Portland cement, Louisville, a natural cement, Fort Scott, a natural cement. The Germania is a Portland cement, made in Germany near the border of Belgium. It is classed as one of the leading Portland cements. Its color is a light grayish blue and it is a fine grain cement, working easily under the trowel. The Iola is a Portland cement, made by a plant just lately erected at Iola, Kansas, where natural gas is used as a fuel in calcining. The sample tested was made from the rock at Iola, which was shipped to the Company's plant in Michigan, and made there in order to find out what quality cement could be made from the material at Iola. The plant not being in operation when this test was begun, a sample of this cement was secured. The color of this cement is a little darker gray than the Germania and seems to be coarser as it works harder under the trowel and scratches more. The Louisville is a natural cement made mostly on the Indiana side of the Ohio River, near Louisville, Kentucky. The Fort Scott is a natural cement, made at Fort Scott, Kansas. It is very much like the Louisville. Both have a reddish brown color before mixing; but after setting the Louisville turns to a whiter color than the Fort Scott