Cements, Mortars And Concretes - Their Physical Properties

INTRODUCTION. The purpose of this treatise has been to set forth as concisely as possible the physical properties of cement and cement mix- tures, with principal reference to those properties which concern the engineer. The results of investigations made upon these ma- terials have been examined with great care. Engineers desiring such data on cements, mortars and concretes, have hitherto been obliged to refer to numerous scattered articles and books. It has been the authors object to abstract, classify and summarize all the reliable data extant, filling in certain gaps with data of his own. The following headings outline, for the greater part, the scope of the work General Physical Properties Changes in Volume When Setting. Coefficient of Expansion Due to Temperature Changes. The Action of Sea Water and Salt. Porosity and Impermeability. Effect of Freezing. Adhesion of Iron Rods to Cement Mixtures. Fatigue of Cement Mixtures. General Elastic Properties Tensile and Compressive Properties. Coefficient of Elasticity, Elastic Limit. Ultimate Resistance. Flexural Properties. Coefficient of Elasticity. Modulus of Rupture. Shearing Resistance. The sources from which the experimental data have been ob- tained are furnished, in every instance, with those data it is iv therefore unnecessary to give separate credit to the various ex- perimeriters atthis point. It is proper to say, however, that use has beenrrratfe only of those results which gave evidence of care- ful work, so that no conclusions might be invalidated by reason of the unreliability of the experiments. Free use has been made of the Annual Reports of the Watertown, Mass., Arsenal, of the Transactions of the American Society of CivilEngineers, and of the Proceedings of the Institution of Civil Engineers of Great Britain. The experiments, not previously published, made under the authors direction in the laboratories of Columbia University, have also been included. It is believed that the results obtained relating to the elastic properties of the material, such as the values of the coefficients of elasticity .and the ultimate strengths, have been so analyzed that these values may be determined in advance, for any mixture, within small limits of error but future experiments and future improvement in the manufacture of cement mixtures may cause considerable changes in these figures. In order that a cements physical peculiarities may be more clearly comprehended, it has been thought advisable to consider as a preliminary some of the chemical characteristics of cements. In connection with the discussion of chemical compositions, the theories of the setting of cements have therefore been analyzed, and it has been possible to abstract, in an appendix, Mr Clif- ford Richardsons theory as to the constitution of Portland cements. In addition, a chapter, together with an appendix, treating briefly of the ordinary commercial tests has been included. M. S. F. August 22, 1904. ART. CONTENTS. CHAPTER I. CHEMICAL PROPERTIES OF CEMENT. 1 . Theories of Setting I PAGE 2. Chemical Analyses 3 Portland Cements Natural Cements 6 CHAPTER II. PHYSICAL TESTS OF CEMENT. 3. Commercial Physical Tests 9 4- Specific Gravity Tests 10 5. Fineness Test II 6. Test for Time of Setting 13 Action ofPlaster ofParis 14 Temperature Affects Time ofSetting 16 Retarding the Set 17 Temperature Changes During Setting 18 7. Tests of Tensile Strength 8. Ratio ofCompressive and Tensile Strengths 9...