453 



NA TURE 



[March 15, 1906 



change in volume during the process of setting, re- 

 sistance to fire, and other matters of a similar nature. 

 The last section of the book, part iv., is devoted to 

 a description of the various classes of work for which 

 cement concrete is most useful, and the question of 

 reinforced concrete, or concrete-steel, as the author 

 prefers to call it, is taken up. In the last few chapters 

 the methods of applying concrete — both plain and 

 reinforced — in large structures such as subways, 

 arches, reservoirs, retaining walls, dams, &c, are 

 fully explained. The book has a good index. 



(3) The whole question of concrete work, both when 

 used by itself and when employed in combination with 

 steel, or reinforced concrete, as it is technically 

 known, is fully dealt with in this elaborate treatise. 

 The first portion of the book is devoted to the proper- 

 ties of Portland and other cements, and includes an 

 interesting chapter which deals with the chemistry 

 of hydraulic cements, and which has been specially 

 written for the book by a chemist, Mr. S. B. New- 

 berry. The authors then deal with the question of 

 the ordinary standard tests of Portland cement, and 

 quote the recommendations of the French Commission 

 of 1893, and of the special committee of the American 

 Society of Civil Engineers, appointed in 1904. There 

 are a number of first-rate illustrations of the various 

 appliances which are needed, and full explanations 

 are given as to the best way of carrying out these 

 standard tests. In addition to the standard tests, 

 special tests, such as those on compression, adhesion, 

 &c, are also discussed. This portion of the book 

 will be found extremely useful for reference purposes. 



Two chapters deal with the questions of the method 

 of determining the laws of volumes and voids in 

 concrete work, and the right methods of proportion- 

 ing the ingredients used in making are explained in 

 detail. The methods described may seem almost too 

 elaborate, but there is no doubt that it pays well when 

 concrete is to be used on a large scale to spend a 

 considerable amount of time and trouble beforehand 

 in determining exactly the best possible mixtures of 

 cement, sand, and broken stone in order to produce 

 the most economical as well as the strongest concrete 

 suitable for the work which has to be carried out. 



The authors then begin the subject of reinforced 

 concrete, and, after discussing the values which 

 should be used for the moduli of elasticity of concrete, 

 both in tension and compression, go on to deal 

 with the problem of the moment of resistance of a 

 reinforced beam. The formulae obtained are fairly 

 simple, and may be said to be approximately correct, 

 since the neglect of the tensile stress taken up by the 

 concrete is perfectly reasonable in designing such 

 beams. It appears to us very inadvisable in our 

 present state of knowledge to attempt to use extremely 

 elaborate formulae in calculating the strength of re- 

 inforced beams, since the values obtained by different 

 experimenters, and even by the same experimenter, 

 for the moduli of elasticity of concrete differ by such 

 large amounts, and the assumption that the stress- 

 strain diagram is a parabolic curve seems to us quite 

 unwarranted by the experimental data available up to 

 the present time. 



NO. 1898, VOL. 73] 



The authors then give some convenient tables for 

 use in the calculation of the strength of beams and 

 slabs which are continuous over supports, and work 

 out a number of examples to illustrate the use of 

 these tables. In dealing with the mixing of concrete, 

 a number of illustrations is given of the various 

 types of mechanical mixers now used when concrete 

 has to be made on a large scale, including mixers 

 fitted with automatic measuring plants in order to 

 keep the proportions of the various materials abso- 

 lutely uniform. A special chapter in this section has 

 been written for the book by Mr. R. Feret upon the 

 effect of sea-water upon concrete. 



A few chapters then follow on the question of the 

 effect of frost upon concrete, both during the time 

 of depositing the concrete and after the concrete has 

 been deposited, upon the necessary proportions of 

 the various ingredients in order to secure absolute 

 water-tightness in any given mass of concrete, and 

 upon the protection afforded to iron and steel when 

 used in reinforced concrete against fire and rust. The 

 remaining chapters of the book are devoted to details 

 of concrete work in various situations, such as side- 

 walks of streets, floors and walls of buildings, found- 

 ations and piers for bridges, retaining walls, sewers, 

 subways, arches, reservoirs, and tanks, and the most 

 economical method of strengthening such concrete by 

 steel reinforcements. A very good bibliography of 

 the subject, and some appendices dealing with the 

 formulae for the strength of beams, conclude a very 

 valuable book. 



(4) This is a treatise for engineers engaged in the 

 design and construction of works in reinforced con- 

 crete, and is based mainly on American practice. 

 The book is divided into three parts; in part i., for 

 which Mr. Buel is responsible, after a brief explan- 

 ation of the properties of cement concrete and steel, 

 the methods of calculation are dealt with ; simple 

 formulae are deduced for the strength of beams, both 

 for the case when the tensile strength of the concrete 

 is taken into account, and when it is neglected ; the 

 more important of the empirical formulae, such as 

 those due to Thacher, Christophe, and Hatt, are then 

 explained, and two very complete tables are given 

 for the safe loads in reinforced slabs of various spans, 

 based on Thacher's formula. 



The design of reinforced columns is then discussed, 

 and the author by a series of tables shows how closely 

 the strengths of such columns, deduced from the 

 formulas he gives, agree with the actual crushing 

 strengths obtained in a series of tests at the Massa- 

 chusetts Institute of Technology. The application of 

 this system of construction to retaining walls, dams, 

 sewers, &c, is very fully explained, several neat 

 graphical constructions being given ; and in this 

 chapter the author deals with the very important 

 problem of the use of steel reinforcement to prevent 

 the cracks liable to occur in large concrete structures, 

 such as dams and retaining walls, due both to 

 shrinkage in setting and to thermal stresses, and he 

 is of opinion that high carbon steel is more economical 

 for this purpose. 



In the last chapter of this section the testing and 



