Remarks

This Table shows (1) that the coarsely ground cement broke at a higher point when used neat than when finely ground or sifted, but at a much lower point when mixed with sand : (2) that at 25 weeks with 3 of sand the gain was equal to 41 per cent, and with 5 of sand equal to 64 per cent; (3) that the strength of the fine cement with 5 of sand was equal to a greater strain than that of coarse with 3 of sand, especially at the earlier stages. The proportion remaining on a sieve of 5000 per square centimetre (32,257 per sq. inch) was 495 per cent. - J. G.

The resistance of Portland cement to crushing after nine months is greater than that of most building materials, being 3 tons per square inch.

1 Grant's Experiments. 2 From M.P.I.C.E, vol. lxii. p. 149 (Grant).

Table1 Showing The Tensile Strength Of Various Limes, Selenitic And Portland Cements

TABLE1 showing the Tensile Strength of various Limes, Selenitic and Portland Cements, with different proportions of Sand at the end of 12 months. Five of the Briquettes kept dry and five in water. Size 1 1/2" x 1 1/2"=2 1/4 square inches. Form as in Fig. 84, page 174. Sand 96 lbs. per bushel.

Neat Proportion by Volume.

Grey

Lime.

L.

Selenitic

Grey

Lime.

L.

Lias Lime.

N.

Selenitic

Lias

Lime.

N.

Lias Lime. W.P.8.

Selenitic

Lime.

C.

Selenitic Rugby Lias.

Selenitic

Aberthaw

Lime.

Rugby Lias Cement

No. 3. Weight

74 lbs.

Portland

Cement, 114 lbs. p. bushel.

R.

W.P.S. Portland Cement, 120 lbs.

Neat Proportion by Volume.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Neat

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

1059

1050

1243

1460

Neat

1 to 1

..

..

..

..

..

..

.

..

..

..

..

..

..

..

..

..

..

..

762

751

804

913

1 to l

2tol

• •

..

• • •

...

..

..

..

..

..

..

..

..

..

..

..

..

..

536

583

479

551

2 to l

3 to 1

113

154

288

318

108

215

178

296

91

182

278

234

206

340

289

459

176

319

445

486

405

439

3 to 1

4 to 1

99

129

147

314

110

134

141

222

62

138

179

290

133

230

188

330

141

248

370

384

362

315

4 to l

5 to 1

68

102

123

195

73

105

99

162

48

100

163

188

74

174

161

276

91

168

323

321

295

280

5 tol

6 to 1

47

62

90

146

52

61

117

180

41

76

130

167

65

148

. ■ .

171

45

103

254

278

222

225

6 to 1

8 to 1

• •

..

..

..

...

..

..

..

..

..

..

..

• • •

......

..

...

..

..

119

229

157

141

8 to 1

10 to 1

..

.. •

• • •

..

...

..

..

...

...

* • ■

..

..

...

..

..

101

138

116

127

10 to 1

12tol

..

...

...

...

..

...

...

...

...

..

..

..

..

..

73

129

93

96

12 to 1