Tests on Mortars for Free-Standing Chimneys

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Tests on Mortars for Free-Standing Chimneys

Hummel, A.; National Research Council of Canada. Division of Building Research

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Unit masonry used in chimneys is required to resist additional stresses to those which masonry in walls must withstand, and an understanding of the properties of mortars required for these

special conditions of use is therefore necessary. A contribution from Germany to the technical

literature on this subject , 'IVi th particular reference to the influence of various types· of mortars on the elasticity and strength of unit masonry, is provided by the paper for which this translation has been prepared.

The paper was translated by Mr. D.A. Sinclair of the Translations Section of the National

Research Council Library, to whom the Division of Building Research Wishes to record its thanks. Ottawa,

April 1960

R.F. Legget, Director

Technical Translation 886

Title: Tests on mortars for ｦｲ･･Ｍｳｴｾｮ､ｩｮｧ chimneys

(Versuche an Morteln fur freistehende Schornsteine)

Author: A. _Hummel

Reference: ｆｯｲｴｳ｣ｨｲＮｾＮ Forschungen im Bauwesen, ser. D, (24):

5-14, 1956.

1. _{Occasion for and Purpose of Tests}

In ｄｲｲｾ 1056, "Principles for the Construction of Free Standing

Chimneys", section 7 d, the following is laid down :

"Suitable mortars for warm and hot chimneys (cf. section 16) are:

1. _{Lime mortar from 1 part by vol. hydraulic lime and 3 to 4}

parts by vol. sand;

2. Lime cement mortar from 1 part by vol. cement, 3 to 4

parts by vol. hydraulic lime and 10 to 12 parts by vol. sand.

Pressure hydrated lime is not suitable. Mortars of greater

cement; content are not' permissible for warm and hot chimneys (section 16)".

These regulations were based on the experience gained with the earlier building lime standard DIN 1060, in which - from tests on

moist standard lime ｾｯｲｴ｡ｲｾ - the strengths of the different limes

varied to a much greater extent and in general showed a much greater range of strengths than are obtained with the soft mortar test

employed today.

Furthermore, since in the case of chimney mortars not only the strength but also the elastic ductibi1ity is important, doubts

arose concerning the aptness of the above specifications for mortar composition, and especially whether it was right to reject pressure

hydrated lime._,

The North-Rhine Westphalian Minister for Reconstruction charged the Institute of Building Research at the Poly technical Institute of Aachen with the investigation of these problems in March 1952.

With the' assistance of lng. Weishaar, Aachen, then chairman of the Committee on Free-Standing Chimneys, a testing program was

drawn up for the comparative testing of masonry mortars with respect to ｾｴｲ･ｮｧｴｨ and elasticity under low, medium and high temperature

storage condi ti ons , an d the compres s i ve st rengths of assemblies built with these mortars.

During the execution of the tests this plan, which had been approved by the above-mentioned Minister, inspired the chairman of

the Committee for Uniform Building Codes, Ministerialrat Prof.

Dr.-Ing. esh , 1}ledler, Berlin, to initiate compressive tests as well

as some flexural tests, where possible, on masonry assem'Jlies from various mortars, as had already been planned earlier, but not

executed, by Prof. Dr. Gehler of Dresden.

Whereas Prof. Gehler at first intended to load the flexural test bodies perpendicularly to the bed joints, in the plan drawn up with the cooperation of Mr. Heishaar it was deemed more appro-priate, in view of the loads encountered in practice, to apply the

flexural loads in the direction of the bed joints. The plan also

called for flexural tests in which at the same time a uniformly

distributed compressive stress of 10 kg/cm2 _{was to be applied}

per-pendicularly to the bed Joints. The details of the experiments

and their results are given in two separate reports which could

not be printed in full. The present report, which has been revised

for printing, is a condensation of the material, leaving out individual values.

2. ScoQe of the Tests

The tests are divided into preliminary, main and supplementary series.

2.1 Preliminary tests

In the preliminary tests the materials employed were tested

according to the appropriate standards. The materials employed

were:

(a) Blast furnace cement Rh delivered in brown bags and referred to as cement of quality class Z 225;

(b) Pressure hydrated lime from lime plant 0, referred to as ultra-hydrated lime;

(c) Hydraulic lime·, referred to as IN-hydraulic lime, ground, slaked;

(d) High calcium lime·· in powdered form, referred to as white hydrate of lime;

(e) Mortar sand composed of grain sizes 0/0.2, 0.2/1 and 1/3

by weight;

(f) Brick, referred to as Ra-clinker.

Materials (a) to (d) were selected by Mr. Weishaar and sent

on his ordeps to the Institute of Building Research. The sand (e)

was taken from the Institute's stock.

2.2 Main tests

2.2.1 Mortar tests

Six different mortar compositions were chosen and are referred

to hereinafter as M₁ to Ms. M₂ is a mortar according to DIN 1056

and serves as a basic and comparison mortar. The mortar

composi-tions are given in Table II. After being stored under various

conditions (see Table III) up to 90 days they were tested for

flexural strength, compressive strength and compressive elasticity.

2.2.2 Masonry tests

Cubic masonry assemblies were built (38 cm side) from the

clinkers according to 2.1 f) and mortars M₁ to M₆ according to 2.2.1.

After standing for 28 days at +20oC and +5°C they were tested for

compressive strength and unit weight.

2.3 SU")Qlementary tests on masonry

Masonry assemblies 118 cm long, 25 cm thick and 38 cm high

were built in English cross bond from clinkers according to 2.1 f)

and mortars M to M , four examples being provided for each of the

1 4

mortars. After aging for 42 days under standard conditions they

•

••

Translator's note: German 11v'asserkalk" = lime containing more

than 10% silicic acid, alumina and iron; slakes on addition of

water (cf. 3rockhaus der Wissenschaft und der Technik,

Leipzig, 1955) •

Translator's note: German "Weisskalk"

=

lime containing more

were tested for flexural strength with and without lateral pre-compression.

3. ｾ Procedure and Results

3.1 Results of the preliminary tests ｾｮ the building materials

employed

3.1.1 Properties of bla.st furnace ce:nent determined according

to DIN 1164

Weight per litre loose poured: 0.95 kg;

Fineness of grinding: residue on screen 0.9 DIN 1171: 0.91%;

Volume stability: satisfactory;

Hardening: initial 4 hours and 20 min.

full 7 hours and 10 min.

Strength values for w/z

=

0.6, slump 18.3 em:

flexural 'after 3 days 50 kg/cm2;

after 7 days 85 kg/cm2;

after 28 days 105 kg/cm2;

c ompr-e's s , after 3 days 201 kg/cm2;

after 7 days 329 kg/cm2;

after 28 days 450 kg/em2.

The cement was delivered as quality Z 225 and found to have quality Z 325.

In view of its intended application the blast furnace cement was tested for the corresponding strengtb values when stored in

water at +5°C. The results were as follows:

flexural after 3 days 19 kg/cm2; '

after 7 days 48 kg/cm2;

after 28 days 72 kg/em2;

compress. after 3 days 66 kg/cm2;

after 7 days 203 l<g/cm 2;

after 29 days 336 kg/em2.

The ratio of 28-day compressive strengths for storage at +5°

and +200C

3.1.2 Properties of building ｬｩｾ

Since change is under way in the 3ppraisal of limes and this is a period of transition, the pressure hydrated, hydraulic and high calcium limes employed were tested according to both the

earlier building lime standard DIN 1060 and the new draft DIN 1060,

version of June 1952, especially with a view to comparlng the

respective strengths of the earlier moist lime standard mortar and

the new soft lime standard mortar. The strengths were tested

beyond the requirements of the standard sheets up to the age of

90 days. As indicated in Table I, the results correspond

sub-stantially to the former and the new lime standards.

3.1.3 Properties of the brick

Determined from 10 bricks DIN 105, earlier version.

Average dimensions: 24.9· 12.2 • 6.3 cm;

Mean weight per unit vol., air dry: 2.13 kg/dm3

Mean compressive strength: 667 kg/cm2 _{(range of 523 to 782 kg/cm}2_{) .}

On the basis of DIN 105, earlier version, therefore, these are

clinkers. According to DIN 1056 "Principles for the construction

of free-standing chimneys II section 6" only bricks with at least

150 kg/cm2 compressive strength may be used.

3.2 Procedures for main tests and their results

3.2.1 Mortar tests

The compositions of masonry mortars M₁ to M₆ and their fresh

mortar propert ies are gi ven in Tab Le 11. The san d for all the

mortars consisted

of:-15% by wt. fine sand 0/0.2 mm

75% by wt. fine sand 0.2/1 mm

10% by wt. sand 1/3 mm.

Weight per litre of dry sand mixture, loose poured, 1.55 kg.

The chosen compositions cover a broad range of mixing ratios including some extending into the fat range hitherto not permitted.

Mortar prisms 4 • 4 • 16 cm were prepared for flexural and

compressive tests and prisms 10 • 10 • 25 cm for compressive

Since chimneys are built at moderate temperatures, but the mortars may be subjected to rather high and even fluctuating

temperatures in operation, the tests were conducted under various

temperature conditions. The storage conditions selected for the

4 • 4 • 16 em and the 10 • 10 • 25 em prisms are shown in Table III. The mean strength values of ,the masonry mortars under the

storage conditions of Table III are represented in Fig. 1 and 2. The elasticity tests were carried Qut with the aid of Martens

mirrors. Each different ｬｾ｡､ was applied repeatedly until a

constant value €elast. fqr the elastic compressive strain was

obtained. The moduli of elasticity E were computed from the

stresses and the elastic compressive strains.

Because of .t.he r r importance for the present investigation, the

mean values of the mOduli of elasticity are given numerically in

Table IV.

From Table IV the moduli of elasticity for a test age of

28 days are plotted in Fig. 3 against the mortar strength for

con-stant live load and normal storage. Similarly in Fig. 4 for a

test age of 90 days as a function of standard storage and thermal

treatment.

For clarification and subsequent interpretation of the

remark-able phenomena revealed in Fig. 4 the weight per unit volume and

the compressive strengths of the masonry mortars are represented

in Fig. 5 and 6 under the same storage conditions as in Fig. 4.

3.2.2 Tests on masonry cubes of 38 em side'

The assemblies of bricks and mortars N1 to ｾＱＶ were built by

hand from 3/4 bricks in the manner illustrated by Fig. 7 and 8.

They were kept 7 days under moist cloths and then in air. Half the

assemblies were kept at +20° from the start, and the other half

at +5°C.

The mean weights per unit volume and compressive strengths of

the assemblies after aging 28 days are shown in Fig. 9, compared

3.3 Sunplementary masonry tests 118 • 25 • 38 em

The assemblies of bricks and mortars M₁ to M₄ were constructed

in English cross bond as illustrated in Fig. 10. They were kept

at room ｴ･ｾｰ･ｲ｡ｴｵｲ･ for 7 days under moist cloths and then in the

room air.

At the age of 42 days the specimens were tested for flexural

strength by being placed as a beam on two supports at a spacing

of s

=

100 em and applying a single load at the centre of the beam.

The bed joints in this test stood vertical in the room, so that the height of the beam was equal to the thickness of the wall

(25 em).

3.3.1 Tests on masonry specimens without precompression

The flexural strength of the masonry beam which was fitted with cement mortar battens at the points of support and load

application, was computed from the load ｾｴ break P plus the dead

bh2

load, substituting the moment of ｲ･ｳｩｳｴ｡ｮ｣･ｾＮ For the results

see Fig. 13.

3.3.2 Tests on masonry specimens with precompression

In order to ensure uniform'application of the precompression

of 10 kg/cm2 perpendicular to the bed joints the masonry beams first

received flat coatings of mortar on the sides parallel to the bed

joints. The precompression was applied in the manner shown in

Fig. 11, using steel plates and tie bolts.

The correct compression forces were ensured by measuring the

elastic elongation of each separate bolt. The required steel

elongation in the elastic range was not only calculated, but also tested in a pull-test machine.

In order to avoid obstructing the bending of the beam

per-pendicularly to the precomnression forces, i.e., in the plane of

the bed joints, gaps of 2 em width were left open between the steel compression plates.

The testing of the precompressed masonry beam is illustrated in Fig. 12.

and that of the precompression appqratus were taken into account at the breaking load P.

Fig. 13 shows the mean values of the weight per unit volume and the flexural strength of the beams in comparison with the flexural strengths of the mortars.

The 10 kg/em 2 precompression perpendicular to the bending

forces has obviously imparted homogeneity to the masonry. The

breaking surfaces were more laminar instead of staggered (cf. Fig.14 and 15) and the scatters in the individual flexural strength values were reduced.

4. ｅｶ｡ｬｵ｡ｴｩｯｮＮｾｦ Results

The blast furnace cement

Z 325. (From experience

definitely Z 225 quality

it is only an accident.)

employed was found to be of quality it may be said that if a cement of is obtained nowadays from the trade

See SE;ro,.3-.1.1.

4.2 The pressure hydrated lime employed is a highly effective

product even in the soft mortar and has a marked secondary

hardening (Table I). Its high-grade nature is of advantage

within the framework of the present investigation.

4.3 The hydraulic lime eillployed, with a compressive strength of

11 kg/cm2 _{after 28 days just satisfied the standard requirement}

of 10 kg/crn2 _{for soft mortars (Table I). For the purposes of}

the present problem the low strength value is also an advantage.

4.4 The brick used is a heavy, very strong clinker with a unit

weight of 2.13 kg/dm3 _{and a mean compressive strength of}

667 kg/cm2 _{(Sec. 3.1.3).}

4.5 Compressive strengths of the 6 mortars employed as a function

of the curing

The mean compressive strengths of the masonry mortars cured

at +20oC (standard curing) vary between 29 and 97 kg/cm2 _after

28 days, and between 28 and 116 kg/crn2 after 90 days (cf. Fig. 1).

mortar compressive strengths.

Compared with standard curing at +20°, curing at +5°C lowered the compressive strengths of the mortars only in the cases of M

1

(mortar from pressure hydrated lime) and M

5 (high calcium lime

cement mortar). In the other cases it was increased (Fig. 1).

Heat treatment (four hours daily in the electric furnace at 200°C and twenty hours in the room atmosphere, repeated 25 times) resulted in a reduction of compressive strength when it WaS begun

after 28 days, but gave either an insignificant reduction or in some cases an increase of compressive strength when the heat

ｴｲ･｡ｴｾ･ｮｴ was applied only after 60 days' curing (Fig. 1).

In practice, chimney heat will always be applied to the older mortars, so that the latter case will be involved.

According to the compressive strengths given in Fig. 1, the 6 mortars fall into two distinct groups, namely those of lower compressive strength, M

1 (from pressure hydrated lime), M2 (from

hydraulic lime and 'cement, as the comparison ｭｯｾｴ｡ｲ according to DIN 1056), and M₄ (high calcium Llne cement mortar) and the group M₃ (from pressure hydrated 11:11e and cement), M₅ (fat high calcium lime cement mortar) and M₆ (fat hydraulic lime cement mortar) with decidedly higher compressive strengths.

Even from these mortar tests it is noteworthy that the compari-Gon mortar according to DIN 1056 (mortar M

2) has higher strength

values than the mortar from pressure hydrated lime Ｈｾｯｲｴ｡ｲ M ) even

1

though the latter is a high-quality hydraulic lime.

4.6 Moduli of elqsticity of ｴｨｾ 6 mortars used, as a function Qf

the curing

Except for a few variations, Fig. 3 shows the known tendency for the moduli of compressive elasticity to increase with increasing compressive strength, while decreasing, at constant compressive

strength, with increasing live load.

The heat treatment, on the other hand, was found to have a very definite influence on the moduli of elasticity of all the

s t and ar-d curing3.nd qt live loads of 10 and 20 kg/cm2 the moduli of elasticity of the different mortars cover the very wide range

of 11570 to 102500 1{g/cm2 , whe rea s after thermal treatment (curine,

5) not merely is the range narrower, between the limits of 6420

and 27700 kg/cm2_{, but the values are reduced to a fraction of their}

former ones.

This reduction in the moduli of elasticity, which is important for the purposes of the present study, is evidently associated with the reduction of unit weights of the mortars, which shows a similar course (cf. Fig. 5) and which results chiefly from the moisture

changes due to the different curing conditions*. In this

connec-tion it is important to note at the same time the compressive strengths of the mortars in practice change but little under the three most important curing regimes (L₃ , ｌｾＬ Lea).

Especially where ｨｩｾｩ strength clinkers are used, the elastic properties of brick masonry are e s serrtLal.Ly a function of the

elastic ')roperties of the mortar, as the weake't' component. But since in chimneys the flue gases produce t.her-nal stresses of a kind similar to those chosen in the reported tests, the definitely reduced moduli of elasticity due to the heat treatment of the

mortar becomes of decisive importance in answering the question raised at the beginning of the report. It a;·mears no longer: ｣ｯｲｲｾ｣ｴ

to exclude medium stron,g-12-very ｳｴｲｯｮｾＵ _m£3.sonr:£ ｭｯｲｴｾＮＮﾣＮＮｬｾｨ｡ｳ

hitherto been done, from use in ｾｨ･｟ｱｧｮｳｴｲｵ｣ｴｩｯｮ of ｦｲ･･Ｍｳｴｱｮ､ｩｮｾ

warm and hot ｣ｨｩｭｮ･ｾｳｾ｟ｴｨ･ grounns of .inadeggate elasticity.

Elasticity tests on chimney masonry from various mortars cured under ordinary air conditions only will not, at any rate, enable us to choose the yroper mortar for this purpose.

The compressive strengths of the masonry specimens of approxi-mately 38 em edge length ma1e from 6 different masonry mortars

*

A further research project on this discovery of considerable

importance for the building trades is now under way at the Institut fUr 3auforschung, Aachen.

showed the following variations (Fig. 9):

Curing at +20oC, from 238 to 299 kg/cm2 _{(mean value 274 kg/cm}2 ₎

Curing at + 5°C, from 200 to 314 kg/cm2 (mean value 275 kg/cm2 _{) .}

Curing at +5°C, compared with that at +20oC, reduced the compressive

strengths of the masonry made with mortars M₁ to M , but increased

, 3

the others somewhat.

The scatters of the masonry compressive strength values around

the means (274 and 275 kg/cm2_{, respectively)}

are:-Curing at +20oC: + 2.9, ±O,

Curing at + 5°C: -27.2, +5.1,

+9.1, -13.1, +0.7, + 1.1% +6.2, - 6.2, +8.4, +14.1%. Thus mortars M

1, M2 and M4 , with compressive strengths of 29

to 43 kg/cm2 _{gave practically the same masonry values as mortars}

M₃ , ｍｾＬ and M

6 with compressive strengths of 83 to 97 kg/cm

2 _•

This unexpected result is explained by the fact that the masonry compressive strength expresses a slab strength value of the mortar,

not its cubic compressive strength. The slab strength increases

compared with the cube strength more in the case of mortars of low compressive strength than for those of higher compressive cube strength, thus tending to equalize the slab strengths, so that, especially where high grade clinkers are used, the range of masonry strength values is also narrowed.

4.8 Flexural strengths of the masonry beams from different masonry

mortars

The flexural strengths of masonry specimens from four different

mortars at the age of 42 days (Fig. 13) are 21 to 27 kg/cm2 _without

precompression and. 28 to 34 kg/cm2 _{wi th precompression.}

Thus the flexural strengths of the precompressed beams for the respective series were 1.39, 1.15, 1.26 and 1.33 times, or an average of 1.28 times, that of the none-precompressed specimens.

No clear relationship could be established between the flexural strength of the masonry and that of the mortar.

Toe precompression of 10 kg/cm2 imparted homogeneity to the

4.9 The rat10 of compress1ve strength to flexqral strength-lg the masonry assemb11es

The rat10 of compressive strength of the masonry after 28 days to the flexural strength after 42 days 1s calculated 1n Table V.

5. Conclus1ons

The pr1nc1pal results of the 1nvest1gat1ons are as follows: The fact that the modu11 ofelast1c1ty of mortars of d1fferent strength are reduced by heat treatment to a fract10n of the1r value for cur1ng at room temperature and that the1r range is cons1derably narrowed renders it no longer justifiable to exclude the use of stronger mortars from mixtures of higher cement content and with additions of pressure hydrated lime for warm and hot chimneys. This is all the more true in view of the fact that according to recent experience the strengths of commercial hydraulic limes vary

widely and narrow strength limits cannot be guaranteed. Whether

looked at from the standpo1nt of the elastic propert1es of the mortar or from that of the strength values of the masonry, all mortar compositions fal11ng within the limits considered in the present paper can be regarded as suitable for ch1mneys.

A 10 kg/cm2 _{precompression app11ed perpend1cularly to the}

plane of bending increased the flexural strength of the masonry beam, within the scope of the present experiments, by 1.28 times the value for the non-compressed specimen.

Table I

Mean values of the most important results of the standard tests on building limes

Kind of lime

Properties _Pressure High

hydrated Hydraulic _(powder)calcium

1 2 3 4

Weight per litre kg 0.82 0.76 0.53

Fineness of grain

%

by wt. residue on 0.09 DIN 1171 3.1 30.0 4.9

0.20 DIN 1171 0.02 11.2 0.1

Constancy of volume O.K. partly O.K. O.K.

--Compressive strength kg/cm2

according to DIN 1060 age

(moist standard mortar)

7 days 152 39

-28 days 258 69

-90 days* 393 140

-Soft standard mortar according

to DIN 1060 new

Flexural strength kg/cm2 _{7 days 18 2}

-28 days 37 6

-90 days* 50 6

-Compressive str. kg/cm2 _{7 days 58 6}

-28 days 164 11

-90 days* 266 29

Mixing proportions, stiffness and weight per unit volume of masonry mortars

1 Mixing proportions Mean slump in TNt. per

Mortar

.Grts

by volume

I

em according unit vol.

Parts by weight to DIN 1164 kg/dm3

1

-1

2 3 4 5

1 pressure hyd , lime 1 pressure hyde lime

M₁ 3.5 sand 6.6 sand 17.5 2.11

1.2 water 1.46 water

1 cement 1 cement

t12 3

hydraulic lime 2.43 hydraulic lime

16.3 2.00

10 sand 16.3 sand

3.73 wate r 3.92 water

-1 cement 1 cement

M₃ 2 pressure hyde lime 1.73 pressure hyde lime 16.1 2.01

8 sand 13.0 sand

2.62 water 2.76 water

1 cement 1 cement

M4 2 high calc. lime

1.12 high calc. lime

16.4 2.02

8 sand 13.0 sand

2 .60 1AJat e r 2.74 water

1 cement 1 cement

f1₅ 1 high calc. lime 0.56 high calc. lime 16.7 2.04

5 sand 8.2 sand

1.65 water 1.74 Nater

1 cement 1 ce:nent

Ms 1 hydraulic lime 0.81 hydraulic lime 16.6 2.02

5 sand 8.2 sand 1.67 water 1.76 water I r-' en I

Curtng cunditions and test age of 4 • 4 • 16 cm and 10 • 10 • 25 cm

ｰｾｩｳｭｳ of masonry mortar

Curing successively in Type of

curing

Humid box I, Room air dry Fluctu'3.ting_temp.* Room air dry _{4 • 4 . 16}Prisms

Test age in days Prisms cm f 10 • 10 . 25 cm - : I I ! I I 1 2 3 4 5 6 7 L, L2 7 days 20° 7 days 20° 21 days 20° 7 28 28 and 90 L ₃ L₄ 7 days 20° 7 days 20° 83 days 20° -- I 90 90

._---ｌｾ 7 days 20° 90 90 I ｾ --J I L₆

-

_L 7 7 days 5° 7 days 5° 20° 28 90 28 and 90 90 90 5 days 20° 5 days 20° 25 days 25 days 53 days 5° 21 days 5° +32 days 20° 5° 5° days days Lab L_aa

----+:

-I- I I I -

ＮＭＭＭＭＭＭＭｾＭ

* The prisms were cured every day for four hours at 200°C in the electric bOX, then 20 hours in the

Mean values of the moduli of elasticity of the masonry mortars

Hoduli of elasttcity E

=

€ d

ke/cm

2 ,--..

I-t ｾＬ e Las b.

a5 I

-At s br-es s d 90 days 90

dar

ｾ･ＮＮＮＬ

I I-t 0_c""'--'"r--!CJ ₂₈ ｣ＮｐＢｾＧｓ _{28 days} 0(\ days 90 d ay s 90 day::; Repeated on "Rep€'ate on

nrisms prisms

;:: ,.c' _{ＧｾＢｬｲ '.ne 2} Cnrin3 h Cu r tng 3 Curing .5 Curing 8b

!'3 _{kg/cm 2} accord. to ｡｣ﾷＺＺｯｲｴｾ .• ｾｯ [-< Curing '2 _{Cuｾ in'"} 1 2 3 4 5 6 7 8 9 4 - 31100 - - - - -5 57400 24000 57600 16600 12800 - 38400 M1 10 50700 - 53000 16200 12900 34700 34700 15 42700 - 47800 16300 12300 31600 26800 20 - - 40100 16200 - 28900 -5 47600 48100 11723 4920 3737 11550 48100 M2 10 34300 41400 11570 6420 4565 9900 41300 15 23300 33900 12870 7097 - 11010 36770 20 - - 14450 - - 12425 33170 10 85200 1:<2900 72200 12300 24800 74000 120600 M 3 20 69800 115300 64400 16300 29500 68400 115600 30 62500 106700 63800 19900 33300 65700 110800 40 55900 96600 62600 22200 35900 64400 104700 5 70900 78300 68900 15300 14700 69200 73000 M4 10 62400 67800 63400 16200 16100 64100 68000 15 48000 53500 54900 16900 17300 58000 60900 20 35100 41500 48900 18200 16600 41400 51600 10 129100 151400 92700 23800 33000 86300 106300 M 5 20 78500 117900 79100 27700 37900 80100 95300 30 64900 90400 71500 30100 39500 74100 88600 40 - - 63600 31100 41300 67200 85300 10 113700 106200 102600 21300 24800 110300 102900 M6 20 103300 96200 86900 26300 29000 98300 92600 30 89400 86800 82450 28ROO 29800 91800 88700 40 75900 79900 80200 28600 27300 88000 37600 I ｾ CP I

Table

y.

Ratio of compressive strength to flexural strength of

masonry specimen

-

-Masonry Ratio of compressive strength to flexural strength

speclmen

-from Beam ｾＢＱｬ thout Beam with

mortar precompresslon precompression

-

-1 2 3

-M1 282 _12.2 ＲＸｾ

₌

_8.8

23

=

32 -M2 274 10.1 274

=

8.8 27

=

31 M₃ ｾ :: 11.0 299

=

8.8 27 34 M₄ 238

₌

11.3 238

₌

8.5 21 28 Mean = 11.2

₌

8.7

I N o I 32 ｾ

,

ｩｾ

\

_.

\

\ - - M 3 ----MI# - - - 1 ' 15 1 I ---M8 30 25_{1 I I ..ＺｉｾＮ Q} 10₁ I -_{] .;prI} I)_\ I \ I / ' I_{. .'} I '1 51 I': I ｔｾﾷ F'" ｜Ｎｾ ...｢ＬｾＭｾｯ I I Ｎｌｾ

..

eo f:; Qj r..201

I

J'

I"

I - \d

i \

I

i I i I

I

"w

I I

ｾ ,'1. I'. : ｾｾＮＮ ; ! _I

•

...

_III

'"

,

:; 151 I,' 1_ 1__ I \\, // I / I \ I I

....

rz. kgfcnrZ ----1'1, - - I ' 1 Z 1 I - - 1 ' 1 3 1 --1'11#

_m_

1'15 I I --- 1'1.I 1_ ｫ｡Ｍﾷｾ 110 o ＵＰＱＭＭＭＭＭＭＭｖＭＭＫＭＭｾ］｟ＫｾＫ｟｟｟Ｋ｟ＮＮＬｌＭｩ｟｟｟｟｟｟｟Ｋ l1f 1 z

•

s 7 8a. 2 6 a ｾ Cnring 5 7 1Ja. Fig. 1 _{Fig. 2}

Compressive strengths of mortars as a function of the

curing conditions

Flexural strengths of maGonry mortars as a function of

"d 110 of03kgj 72, I I'J ... I ".6 5 ab Curir:e 20

In.,

10 I ! !

oU

3 ｾｾ

\

L __

---+ 90 , • or' - - - M1 - - H 2 - - M 3 _ . - 1'111 - · · · - M 5 •••••••-.-- 1'16 o (J10

..

ｾｉ｜

\

'I; • (120 If 70 \ \ \\ \ ｲＭＭｾＭﾷＭＭＭＭＭ c

.-- ,.\' '.., l

60

ｾｾｴｾ

\ \\\

1---.--

'\

'.. ｾＺ i \ \,\, '1 ＵＳＬｯｾ \ '\; l 50

ｾ｜｜

ｾｴＭＭＭ

--- -_. ,

::. ＢＸｪｽＧｾ｜ ' \ \ ' \ \ 6 I \ ' , 'J I ' \ ｾ , e.., "0 "0.7; \\

\J

--!---l { i \\ I \ '\ c. I \ ｾ ;:J I \ ｾ 30 I \ ' n c H6 ＹＷｾＯｃＱＱＡＲ 1'15 M3 83 ell str<>!;fth H2 H/I 35 /13 Ccnnressive H7 29 20 30 50 11 v: -' c. Eft) :> .,...: 1.'. c. 'I.' 71 H 8 861 y"> +' fa, 0" l ' r ' ..., CI 9, .c::' ｾ Q

".

( Fig. 3 Fig. 4

Moduli of elasticity as a function

of mortar strength (28 days'

standard curing L ₂)

Moduli of elasticity as a function

of standard curing L₃ and heat

treatments ｌｾ and Lab

I l"J N I 8a -5 Cur;r:? 3 ＯｾＺ 7r- ./ L116 •. / '• ｾＺＺＮＮＮ

-,

' 1 - -;

＾ｾ ｾＵ

" , \102

./ "r..::,

'0 ｾ

0...

•..ﾷｾＹＰＭ 10 ". lJ6 ｾｏ ---1'11 - - 1 ' 1 2 , - - 1'13 - - - r - - , 10 ---1'1'1 ---1'15 ----"--.-- 1'16 ｲｯｌＭｬＭＭＭＭｾｉＭＭＭｮ ;0 ｾ _ ...·{!L·_-_W 1 0

-r-.

w ｾｾ ｾｾ 2,... - : : - - - 23 , ... 16 ,L. I 1 10 30 20 '10 100 111 G.J 71 ｾ on II: ec CJ61

,.

p, e o tJ50 .s;::90 .p L) ｾ Cl; 1- III +" U. 121 lib 5 Curine 3 ----1'11 .!l - 1 ' 1 2

}.

- - 1 ' 1 3 - _-_MIJ \ \ ----1'15 1\ \'\ ---.---1'16 1

1\\\ \.

..._ｾ

\\

...

.

1\ \.\ .... \

\\.

\,

\ "1\ ...

/

\,

\.\

<, ｾ \,_{. i\}

':.

\

····.L

I \\\ ｾ ..ｾＺＢ

1\

ｾＲ \

\\

/"\.

.-.

ｾＱ

\

':.

/

"

,

\

... I

\

'11 \ 17 \ r <, s _<, ｾ

-1.'" F' 1,7 1,71 1,8 1,1/, 1,7; 1.90 ..., 1,113

....

.£ 1,112 ..-1,92 1,93 1,7, 1,91 1,1/9 1,118 1,87 += 1,1/6 .c

_:l

1,1/5 IV_{ｾ 1,11·} 1,9'1 Fig. 5 Fig. 6

Un1t weights of mortar for standard

curing L₃ and thermal treatments

L_{s and} Lab (gO-day values)

Mortar compressive strength at standard

curing L₃ and heat treatments

ｾ ｾ 1st and 3rd course 2nd ｣ｯｵｾｳ･ Fig. 7 Masonry bond . "J ＱＧＱｾ 1'15 Mortar designation Masonrv_"" ｳｾ･｣ｩｭ･ｮ_... after 28 ､｡ｹｳｾ _{... +----+} Mor tpr after 28 na.ys0-_-<> +_..._+ I : /"2 I N ｾ I 0 - - - _ - 0 day s+__••• _.+ unit wt. after 28 ｾＹＮｳｃＡＱｲｖ Fig. 8 Masonry specimen Fig. 9

Unit weights and compressive strengths of masonry specimens aged 28 days,

Fig. 10

Masonry specimen for flexural testing

Application of precompression to masonry beam

Fig. 12

Flexural testing of pre-compressed beam

5 Z 32

J

»:

ｾＮ

ｾＧＭＧＭｦＧＮＯ

-,

0

17

-,

28

/ "

Ｂｾ

V

_ｾｾＱ

/.;,- , I " / ...11i / I I ＭＮｾ / ｾ 'Ii},'

/

Irq/<

-'.

' ....ＮＺ［ｾｉｩ ｾ -,

,

ｾ 2.13 _1'13ｾ "''1\, _{11••••»>"} 4 o /'11 _r/2AA _{/'13 /'111} Mortar designation 5 3 10 3

Jc#m

+---+ Mortar after 28 ､｡ｹｾ

0 - - - 0 Masonry assembly after 42 days with precompression

i . - - - . X Masonry assembly after 42 days without precompression

0,···0 Unit weight of masonry after 42 da.ys

Fig. 13

Unit weights and flexural strengths of masonry beams without and with precompression at age of 42 days compared with

" ' - - - 1 1 7 , 2 - - - . - 1

Remark: without cocpression

Fig. 14

Break path in beam from mortar M₃

without precompression

" " 1 7 7 , 7 '

-Remark: with 10 kg/cm2 precompression

Fig. 15

Break path in beam from mortar M₃