Experimental researches on the constitution of hydraulic mortars,

Mode of access: Internet.

Sunto delle conoscenze positive attuali circa le qualità, la scelta e la reciproca convenienza de' materiali atti alla fabbricazione delle malte e de' cementi calcarei : seguitato da note e da prospetti di sperimenti giustificativi /

Spine title: Malte e de' cementi calcarei.

Mihrab

11 ft. 3 5/64 in. x 9 ft. 5 21/32 in.; mosaic of polychrome-glazed cut tiles on stone-paste (fritware) body; set into mortar

Chaux, ciments et mortiers,

Mode of access: Internet.

Workability of mass concrete.

Mode of access: Internet.

The foes of our own household.

The instant need ; and the ultimate need -- Must we be brayed in a mortar before our folly depart from us? -- The children of the crucible -- Washington and Lincoln -- A square deal in law enforcement -- Industrial justice ; the tool-owner and the tool-user -- Social justice ; the brotherly court of Philadelphia -- Socialism versus social reform -- The farmer ; the corner-stone of civilization -- The word of Micah ; the religion of service -- The parasite woman ; the only indispensable citizen -- Birth reform ; from the positive, not the negative side -- Appendix A. Why we are at war ; the German horror -- Appendix B. Fair play for all Americans -- Appendix C. Murder is not debatable -- Appendix D. The "conscientious objector." -- Appendix E. The Hun within our gates -- Appendix F. Nine-tenths of wisdom is being wise in time -- Appendix G. Correspondence with the President and the secretary of war.

Papers presented at the Boston meeting, under the auspices of the Linnaean Fern Chapter, August 24, 1898.

Cover title.

A narrative of many surprising conversions in Northampton and vicinity.

Mode of access: Internet.

Recherches sur la préparation que les Romains donnoient à la chaux : dont ils se servoient pour leurs constructions & sur la composition & l'emploi de leurs mortiers /

Title vingnette; head- and tail-pieces.

An address delivered before the Worcester Agricultural Society, October 20, 1831 : being their thirteenth anniversary cattle show and exhibtion of manufactures /

Bruntjen, S. Amer. imprints,

The minister of Christ and his message delineated : A sermon, delivered at the installation of the Rev. Preserved Smith, over the church and society in Rowe; December 2, 1812: /

Shaw & Shoemaker

A handbook of rocks, for use without the petrographic microscope,

Mode of access: Internet.

The control of alkali silica reaction using blended cements

It has been previously established that alkali silica reaction (ASR) in concrete may be controlled by blending Portland cement with suitable hydraulic or pozzolanic materials. The controlling mechanism has been attributed to the dilution of the cement's alkali content and reduced mobility of ions in concrete's pore solution. In this project an attempt has been made to identify the factors which influence the relative importance of each mechanism in the overall suppression of the reaction by the use of blended cements. The relationship between the pore solution alkalinity and ASR was explored by the use of expansive mortar bars submerged in alkaline solutions of varying concentration. This technique enabled the blended cement's control over expansion to be assessed at given `pore solution' alkali concentrations. It was established that the cement blend, the concentration and quantity of alkali present in the pore solution were the factors which determined the rate and extent of ASR. The release of alkalis into solution by Portland cements of various alkali content was studied by analysis of pore solution samples expressed from mature specimens. The specification for avoiding ASR by alkali limitation, both by alkali content of cement and the total quantity of alkali were considered. The effect on the pore solution alkalinity when a range of Portland cements were blended with various replacement materials was measured. It was found that the relationship between the type of replacement material, its alkali content and that of the cement were the factors which primarily determined the extent of the pore solution alkali dilution effect. It was confirmed that salts of alkali metals of the kinds found as common concrete contaminants were able to increase the pore solution hydroxyl ion concentration significantly. The increase was limited by the finite anion complexing ability of the cement.

Chloride resistance and durability of cement paste and concrete containing metakaolin

Metakaolin (MK), a calcined clay, was included as a partial cement replacement material, at up to 20% by weight of binder, in cement pastes and concrete, and its influence on the resistance to chloride ingress investigated. Reductions in effective chloride diffusion coefficients through hardened cement paste were obtained for binary blends and by combining OPC, MK and a second cement replacement material of pulverised fuel ash or ground granulated blast furnace slag. Steady state oxygen diffusion measurements through hardened cement pastes measured using an electrochemical cell showed that the interaction between charged species and the pore surfaces is a major factor in determining chloride diffusion rate. Rheology of the binder, particularly at high MK replacement levels, was found to have a dramatic influence on the diffusion performance of cement pastes. It was concluded that plasticising admixtures are essential for adequate dispersion of MK in cement pastes. Chloride concentration profile analysis of the concrete cylinders, exposed to sodium chloride solution for one year, was employed to obtain apparent chloride diffusion coefficients for concrete specimens. MK was found to reduce the depth of chloride penetration into concrete when compared with that of unblended mixes. Corrosion rate and corrosion potential measurements were taken on steel bars embedded in concrete exposed to a saline environment under conditions of cyclic wetting and drying. The initiation time for corrosion was found to be significantly longer for MK blended mixes than for plain OPC systems. The aggregate-paste interfacial zone of MK blended systems was investigated by steady state diffusion of chloride ions through mortar containing glass beads as model aggregate. For the model aggregate specimens tested the work confirmed the hypothesis that properties of the bulk paste are the controlling factors in ionic diffusion through mortar.

Use of colour image analysis for assessment of fire damaged concrete

The aim of this project was to carry out a fundamental study to assess the potential of colour image analysis for use in investigations of fire damaged concrete. This involved:(a) Quantification (rather than purely visual assessment) of colour change as an indicator of the thermal history of concrete.(b) Quantification of the nature and intensity of crack development as an indication of the thermal history of concrete, supporting and in addition to, colour change observations.(c) Further understanding of changes in the physical and chemical properties of aggregate and mortar matrix after heating.(d) An indication of the relationship between cracking and non-destructive methods of testing e.g. UPV or Schmidt hammer. Results showed that colour image analysis could be used to quantify the colour changes found when concrete is heated. Development of red colour coincided with significant reduction in compressive strength. Such measurements may be used to determine the thermal history of concrete by providing information regarding the temperature distribution that existed at the height of a fire. The actual colours observed depended on the types of cement and aggregate that were used to make the concrete. With some aggregates it may be more appropriate to only analyse the mortar matrix. Petrographic techniques may also be used to determine the nature and density of cracks developing at elevated temperatures and values of crack density correlate well with measurements of residual compressive strength. Small differences in crack density were observed with different cements and aggregates, although good correlations were always found with the residual compressive strength. Taken together these two techniques can provide further useful information for the evaluation of fire damaged concrete. This is especially so since petrographic analysis can also provide information on the quality of the original concrete such as cement content and water / cement ratio. Concretes made with blended cements tended to produce small differences in physical and chemical properties compared to those made with unblended cements. There is some evidence to suggest that a coarsening of pore structure in blended cements may lead to onset of cracking at lower temperatures. The use of DTA/TGA was of little use in assessing the thermal history of concrete made with blended cements. Corner spalling and sloughing off, as observed in columns, was effectively reproduced in tests on small scale specimens and the crack distributions measured. Relationships between compressive strength/cracking and non-destructive methods of testing are discussed and an outline procedure for site investigations of fire damaged concrete is described.