Thermal and Moisture Expansion Studies of Some Domestic Granites by Arthur Hockman and Daniel W

U. S. Department of Commerce Research Paper RP 2087 National Bureau of Standards Volume 44, April 1950 Part of the Journal of Research of the National Bureau of Standards Thermal and Moisture Expansion Studies of Some Domestic Granites By Arthur Hockman and Daniel W. Kessler As a part of a study of the physical proper ties of b uilding stone, Lh ermal expansion determinations we re made on 48 sa mples of domestic granites by t he d iffcrcntial inter fcrometcr method (w ith an inlerfcrogJ;aph r ccording attachmcnt) over t he tcmperaturc range - 20° to + 60° C. Thermal coe fficients computed between - 20° and + GO° C I'anged from 4.810 8.3 X lO- 6 per d eg C w ith an avcrage of 6.2 X 10- 6 pCI' deg C. Coe ffi cic nts ob La incd on cool ing (GO ° to 0° C) averaged G.7 X 10- 6 p el' d eg C. Expansion cu r vcs dra\\"Il [01' all samplcs indicatc sligh t irrcguJ arilies in lhc 0- to 20-dcg rangc in the healing CUI'I'cs of at least G5 pOl'ce nt of thc samples. These irrcgulari t ies are p r obably callscd by m oi;; lurc changes in lhc sample during Lhc tesL i\[oislurc cxpansion dcLc rminat ions \\'crc madc on t hc 48 sa mples bv mcans of l hc T uckerman oplical strain gagc ovcr a 2"I-hollr pcriod at co nstanL tcmper aturc. Thc cxpan sions obtained r ange d from 0.000-1 to 0.009 percenL and avcraged 0.0039 per ce llt. Advcrsc cff cls r cs ul t ing from continued thcrmal and moi -ture expansion and contrac tion of !!:ran ite arc bel ic \'cd (0 be of SO IllC significance ill monulllcntal ~ trll cl l1l' es lhat arc cxpcclcd to la~ L for long perio::!s o f limc. I. Introduction l'es uHing from the II ual diurnal Lernpe l'ature cllaoges call e internal stresses wh ich, after Granite is known (0 bc one of th e most durablp numerous repetitions, may have a weakening effeeL of structural matcri als. For thi s rca on it has on (h e stone. II also seem likely that the granite been an ideal cllOi c;e for monuments, public build may be a rrectecl by Lhe unequal expansion of the ings, shrines, and structures that arc cxpected to eliA'e rent mineral co nstituents, and t he fact that last for cenLu ries. Therc arc grani tc structlll'cs the pri neipa l constituen ts, namely feldspar and in this country that have existed for periods up quartz, expand unequally along differenL crystal to 200 yr without sho\\-ing serious signs of dis lographic axe. integration, yet there is evidcnce to show t hat Expansion cfl' ects clu e to absorption of water by some granite structlll'{,s have begun to deteriorate granite have not been generally understood or in less than 50 yr. appreciated. The experimental data acq uired The durability of granite may be adversely in this study definitely prove th aL granite llllder affected by one or more of many physical and goes a change in length on becoming wet. As in chemical agencies. The effect of natural temper the case of thermal expansion, the ]'epeated ex ature changes in contributing to the deterioration pansion and contraction res ul ting from wetting of the stone has been recognized by geologists and drying may have a weakening eerect on the and engineers.' It is well known that the rapid stori e. M oist ure grad ien ts resulting from partial heating of granite, as in the case of a fire , will \\-et ti ng of the tone cause internal stresses, which usually cause serious spaUing. 1\ot so apparent in th e co urse of time may adversely affect its is the fact that gradients in a graniLe s Lructure durability. 1 T he supposition that rocks in ge neral arc seriously affected by natural The pLll'pose of this study was to accumulate changes ill temperature is strongly chall enged by some geologists. For data on the thermal expansion characteristics of "xample sec E. 13Jackwelder, Tbe insolation hypothesis or rock weathering Am. J. Sci. 2 6, 970 ( 1933) . grallite over the temperature range produced by Expansion of Domestic Granites 395 the usual weather exposures and also on the TABLE 1. Summary of thermal ex pansion data on granite expansion due to the absorption of water. Most obt ained by previous investigators of the published data on thermal expansion 'of Mean co granite were computed from measuremen ts taken effi cient of No. of Temperature linear ther- Date of at larger temperature intervals than those to specimens ran ge a m~ l expan- Inves tigator publi c tested SIOn per ation which masonry is normally subjected , and these degree CXIO ' values can be misleading when applied to the seasonal range. In this study coefficients of °C linear thermal expansion were determined over L _________ - 14 to +39 8. 25 Bartlett. _________________ . 1832 L _________ +10 to 98 8.22 Adie ______________________ 1836 the range of - 20° to + 60° C (_4° to 140° F) , 4 _____ ________________ ___ _ 8.85 Heade ______________ _______ 1886 ll _________ _ o to 100 b 7.0 \Vatcrtown ArsenaL ______ 1895 Since there are very few data published on the L _________ _ o to 100 10. 2 Bald win-'V iseman & 1909 moisture expansion of granite, this property was Gr iffi th . determined on the entire series of samples tested L __________ + 19 to 172 8.6 Wheeler. __________________ 1910 20 __________ 0 to 100 8. 1 Griffith ____ _______________ 1936 for thermal expansion. This report cites a few 5_________ __ 3 to 60 6. i Willis & DeReus ___ _______ 1939 examples of granite structures that show some 4___________ -20 to 60 6. 0 Johnson & ParsoDs ________ 1944 deterioration result ing from temperature and n The ran ge for which t he coeffi cients were calculated. moisture eff ects. b Specimens tested in wet condition. II. Previous Investigations stones, marbles, and one sample of granite (P eter A review of the literature on thermal expansion head, Scotland). The temperature range was m easurements of gra~it e reveals that in 1832, + 20° to 300° C. In 1910, Wheeler [6] studied Bartlett [1] 2 seeking the cause of fissures in coping th e eff ects of six repeated heatings from + 1 go to joints in a granite structure, m easured the ther 1,000° C of samples of Rhode Island granite, mal expansion of a sample of Massachusetts Canadian diabase, and of Italian marble from granite, and samples of m arble and limestone, + 19 ° to 500° C. His specimens were 94 in, long, and the tempera The more recent investigations of 'thermal ture range was - 14° to +39° C . (See table 1 expansion include those made in 1936 by Griffith for results of previous investigations). Also [7]. Among the 106 samples of American rocks about this time, Adie [2] m easured the expansion tested by him, about 20 represent granites gen of two granites (Aberdeen gray and P eterhead erally used for building and monumental purposes. red from Scotland), also samples of marble, sand His range was room temperature to 260° C. stone, and greenstone, 11 is temperature range In 1939, Willis and D eR eus [8] included the was + 10° to 98° C. Adie recognized that a m easurem en ts of five samples of granite in their sample of greenstone expanded permanently study of concrete aggregate, The temperature after several successive heatings. R eade [3] in range was + 3° to 60° C. In 1944, Johnson and 1886, included four samples of grani te in his ther Parsons [9], a pplying a test procedure similar to mal expansi on studies of several types of rocks that used in the present investigation, included but did not state the temperature range, In the m easurem ents of four granite samples in their 1895 at the Watertown Arsenal [4] thermal ex study of thermal expansion of concrete aggregates. pansion tests were made on eleven samples of Comparatively few investigators have studied granite acquired from eight states. Measured the moisture expansion of building ston e. It bars, 24 in. by 6 in. by 4 in. were placed in cold seems that in 1886 Schumann [10] (original refer water (32° F ), then in hot water (212° F ), and ence unobtainable) was the first to make a syste back in the cold bath. These expansion results m atic study of moisture expansion of natural eviden tly represen ted the combined eff ects of stone. Hirschwald [11] repeated th ese experi temperature and moisture. m en ts. Using a micrometer microscope, th e latter In 1909 Baldwin-Wiseman and Griffith [5] determined length changes of several stone speci determined permanent length changes, due to m ens after 2 weeks immersion in water. The heating, for several samples of sandstones, lime- average expansion obtained for one sample of granite and four samples of basalt was 0.029 2 Figures in brackets indicate thc literature references at the end of this paper. per'cen t. 396 Journal of Research --, More r ecent studies of moisture expansion of in the rock, the more abundant usually bein g a building stone include those made by Matsumoto potash feldspar (orthoclase or microcline or both). (12), Stradling (1 3), Royan (14), and K essler [1 5]. The other is soda-lime feldspar (plagioclase) , and However, the reports of these investig ators did may include one or more of the following spec ies: not include any data on granite.

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