PSI - Issue 37

João Custódio et al. / Procedia Structural Integrity 37 (2022) 644–651 João Custódio et al. / Structural Integrity Procedia 00 (2019) 000 – 000

648

5

4. Results and discussion 4.1. Heat of hydration

The results obtained in the binder heat of hydration determinations already made by semi-adiabatic calorimetry (NP EN 196-9) and by isothermal conduction calorimetry (NP EN 196-11) are presented in Table 3 and Fig. 3. From the results obtained, it was observed that the isothermal conduction calorimetry method tends to give slightly lower values of heat of hydration (-11 % to -18 % when compared to Q 120h,EN196-9 and (-6 % to -15 % when compared to Q 41h,EN196-9 ). It was also found that the best correlation, between the two test methods for the cements assessed, was obtained when using the values at 41 hours from the semi-adiabatic calorimetry method and at 168 hours from the isothermal conduction calorimetry method. Table 3. Results obtained in the binder heat of hydration determination tests.

Heat of hydration Q 120h,EN196-9 (J/g)

Binder

Q 41h,EN196-9 (J/g)

Q 168h,EN196-11 (J/g)

CEM II/A-L 42,5 R

314 389 379 399 336 325 394 349 343 326

331 403 390 409 344 335 395 362 364 340

295 333 324 337 307 296 335 310 308

CEM I 52,5 R CEM I 52,5 R CEM I 52,5 R

CEM II/A-L 42,5 R CEM II/A-L 42,5 R

CEM I 52,5 R

CEM IV/A (P) 42,5 R CEM IV/A (P) 42,5 R CEM II/B-M (S-L) 42,5 R

300 NOTATION: Q 41h,EN196-9 (J/g) – heat of hydration, Q, in joules per gram of cement, at 41 hours, measured by means of semi-adiabatic calorimetry; Q 120h,EN196-9 (J/g) – heat of hydration, Q, in joules per gram of cement, at 120 hours, measured by means of semi-adiabatic calorimetry; Q 168h,EN196-11 (J/g) – heat of hydration, Q, in joules per gram of cement, at 168 hours, measured by means of isothermal conduction calorimetry.

420

410

y = 1.94x - 255.46 R² = 0.99 y = 1.79x - 195.90 R² = 0.96

400

390

380

370

360

350

340

Q41h,NP EN 196-9 vs Q168h,NP EN 196-11 (experimental values) Q120h,NP EN 196-9 vs Q168h,NP EN 196 11 (experimental values) Linear (Q41h,NP EN 196-9 vs Q168h,NP EN 196-11 (experimental values)) Linear (Q120h,NP EN 196-9 vs Q168h,NP EN 196-11 (experimental values))

330 Q (J/g) NP EN 196-9:2010

320

310

300

270 280 290 300 310 320 330 340 350 360 370

Q (J/g) NP EN 196-11:2020

Fig. 3. Results obtained in the binder heat of hydration determination tests: comparison between the heat of hydration values obtained with the semi-adiabatic (NP EN 196-9) and isothermal conduction (NP EN 196-11) calorimetry methods.