Page 15 - Minutes of Proceedings of Civil Engineers Vol CXCV 1913-14 Part 3 Correspondence

130 coRnnspoNDtrNcE oN TIIE coNsTEUcrIoN oF [Minuterol Mr. Ooulchor. .iYo. f was a hnrd concrete, rather dark in colour on the face, the interior being of o lighter colour to a depth of about I inchfrom the fnce, whero the colour assumed a mucir bluer tint, suggesting some permeation of sea-water to this depth, the darker portion being apporently unntL.rcked. .iVo. 2 consisted of a mass of aggregato covered rvith rvhite irrcnrshrtiorr nnd much whito porvdery materi:rl, and appe&red to bo n tlrorrrrrghly decomposed and disintegrated concrete, leoving nothing brrt ngglegato and a small portion of decomposed cement. Mr. llutltrr found by anrlysis that the fine matrix and cement conttinod tho following percenttges of lime, magnesia, and sulphuric nnlrl'rlrirlo :- ,*,:litl3,ill;*. o,.*llil.xl8,l*&nn;*,". r,irne. ."r";:;?" "iil';',it' Magnesirr. 2'74 72'82 Sulphuric Auh;'rh itlc I '69 6'95 I)arlucting s.rnd and extraneous rnntter, the calculnted pelcentages of lime, magnesia, and sulphuric anhydride in the cement, or material other thnn santl and aggregate, were apploximately:- i1lf.,,'l?XJ;l;. u,.,,,L1iTl'Ji,\-l;';**. Per Cent. l,irno 58'85 Per 00rt, 35'04 Mrgtresil . 4'94 23'89 Sulphulic Atth;'tlu.re 3'05 12'05 Mr. lhrtJel in his reporb sairl :- " Tho nbovo shrrvs tirat the cernent in the good concrete has beeu l'ut rery littlo tlfet:terl ly the sea-rvater, its composition, rvith the excepbion of e slight oxr:ors of nrlplrulic ocid en