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(5) |
In addition to the capability of writing the final hydrated microstructure to a file, depending on user input, between four and seven additional files are created during the execution of disrealnew. The first of these contains a log of the program execution and is written to stdout (standard output). Thus, to save this to file, the user would typically pipe the output (using the > character), perhaps using a command line of the form:
This file (disreal3d.out) will contain a listing of all user inputs, the number of diffusing species created during each dissolution, the number of pixels of each phase present during each cycle, data on self-desiccation, and information on the assessment of percolation properties of the pore space and the total solids.disrealnew <disreal3d.dat >disreal3d.out
The second file which is always created, phases.out, contains for each cycle the number of pixels of each phase present at the end of execution of the cycle and the number of pixels of water remaining in the system (for hydration under sealed or self-desiccating conditions). These phase counts are given in the order in which the phases are listed (0-25) in the disrealnew.c program provided in Appendix C. An example of the output generated during the first five cycles of a w/c=0.3 hydration run under sealed isothermal (25 ºC) conditions is as follows:
0 489796 338368 63402 39873 40500 28061 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 489796 1 488899 338368 63402 39776 40395 27660 0 0 0 0 0 0 28 0 0 701 620 0 52 0 0 0 0 0 0 0 77 488899 2 488017 338288 63398 39686 40307 27306 0 0 0 0 0 0 58 135 0 1372 1102 0 109 0 0 0 0 0 0 1 150 488017 3 487064 338197 63389 39590 40206 26936 0 0 0 0 0 0 99 301 0 2082 1617 0 164 0 0 0 0 0 0 4 214 487064 4 486205 338116 63382 39499 40115 26600 0 0 0 0 0 0 152 437 2 2683 2119 0 212 0 0 0 0 0 0 5 287 486205 5 485304 338019 63376 39386 40018 26246 0 0 0 0 0 0 208 591 2 3322 2633 0 259 0 0 0 0 0 0 6 389 485304
The first column indicates the hydration cycle number, the second the pixel count for water-filled porosity, the third the pixel count for C3S, etc. The final two columns indicate the empty porosity created due to self-desiccation and the value determined for the water left in the microstructure. For hydration under sealed conditions (as in this example), the value for the water left should be the same as the count for water-filled porosity in the first column of the same row. It can be seen that the phase counts for the clinker phases and gypsum (columns three through seven) are decreasing during the hydration, while those of the hydration products are increasing, as would be expected.
The third file, heat.out, contains for each cycle, the degree of hydration achieved both on a volume and a mass basis and the estimated heat release using four different methods [1], the first based on the specific enthalpy values of each phase and the latter three based on different values for the heats of hydration of each of the four major clinker phases, as documented in the source code listing provided in Appendix C. It is the fourth value that is currently utilized in calculating the temperature rise for hydration under adiabatic conditions [24], and has provided the best fit to experimental data [1,2]. An example output file is as follows:
Cycle alpha_vol alpha_mass heat1 heat2 heat3 heat4 0 0.000000 0.000000 -28530480.000000 0.000000 0.000000 0.000000 1 0.000419 0.000438 -28530894.000000 418.921326 499.942719 620.179260 2 0.000962 0.000994 -28531184.000000 925.209595 1085.318848 1306.325073 3 0.001578 0.001626 -28531820.000000 1489.566772 1734.313965 2070.976318 4 0.002138 0.002199 -28532094.000000 2007.340576 2332.071289 2772.938721 5 0.002788 0.002860 -28531524.000000 2617.215576 3041.136475 3593.079590
Since the entries for heat1 correspond to the current total enthalpy present
in the microstructure, to determine the heat released based on these
values, the user would need to subtract the first entry for this quantity
from all subsequent entries. The values for heat2, heat3, and heat4 are
in units of kJ x pixel/(cm3 of paste x system). To convert to
kJ/(cm3 paste), one can simply divide by the number of pixels in
the system (1003). To further convert to kJ/kg cement, one needs to
divide by the number of kg of cement in a cm3 of paste.
Thus, one calculates the final conversion factor (for a system with only
Portland cement) to be:
This equation becomes more complicated when mineral fillers are present, but the correct equation in this case can be found in the disrealnew.c code in the variable heat_cf, which is used in the adiabatic temperature rise calculation.
The fourth file, adiabatic.out, contains an estimate of the adiabatic heat signature for a concrete or mortar with the 3-D cement paste as its binder component. Here for each cycle, the file contains the estimated equivalent time (age) in hours, the temperature in degrees Celsius, the degree of hydration on a mass basis, the estimated reaction rate at the current temperature (relative to 25 º), the current estimate of the heat capacity of the mortar or concrete in J/g/ ºC, the current mass fraction of cement in the system, and the ratio of the rate constant for the pozzolanic reactions to that for the cement hydration. The current mass fraction of cement value should remain constant unless the hydration is being executed under saturated conditions, in which case the additional water imbibed into the hydrating cement paste will reduce the mass fraction of cement in the overall system. An example output file is as follows;
Time(h) Temperature Alpha Krate Cp_now Mass_cem kpozz/khyd 0.000000 25.000000 0.000000 1.000000 0.000000 0.215337 1.000000 0.000300 25.000000 0.000438 1.000000 0.000000 0.215337 1.000000 0.001200 25.000000 0.000994 1.000000 0.000000 0.215337 1.000000 0.002700 25.000000 0.001626 1.000000 0.000000 0.215337 1.000000 0.004800 25.000000 0.002199 1.000000 0.000000 0.215337 1.000000 0.007500 25.000000 0.002860 1.000000 0.000000 0.215337 1.000000
Note that the values for the heat capacity, Cpnow, are only determined when the hydration is executed under adiabatic conditions and thus are all zero in the example shown (isothermal conditions).
These last three files are in a format that can be easily imported into a spreadsheet or read directly into a plotting package. This allows the user to compare results from different cements, w/c ratios, or hydration conditions or to produce plots of various properties vs. the number of hydration cycles or the estimated equivalent real time for comparison to experimental data, as shown in Figs. 15 and 16.
The fifth through seventh output files are created only when the user elects to regularly assess percolation of the pore space, percolation of total solids, or particle hydration characteristics. The fifth file, percpore.out, contains the results from analyzing the connectivity of the water-filled capillary porosity during the course of the hydration. This file consists of the following four columns: the number of cycles of hydration executed, the degree of hydration on a mass basis, the count for connected pores, and the total porosity count. Each time this option is executed, three lines of output are generated, one for executing the burning algorithm [13] to assess percolation in each of the three principal directions within the 3-D microstructure. Once the water-filled capillary porosity disconnects in all three of these directions (connected count=0), the percolation properties are no longer assessed as the hydration continues, to reduce the program's execution time. An example output file is as follows:
20 0.011002 471448 472885 20 0.011002 471453 472885 20 0.011002 471436 472885 40 0.020940 456515 458401 40 0.020940 456504 458401 40 0.020940 456501 458401 60 0.030379 443423 445768 60 0.030379 443402 445768 60 0.030379 443409 445768 80 0.040059 431470 434408 80 0.040059 431448 434408 80 0.040059 431439 434408 100 0.051172 419360 423136 100 0.051172 419357 423136 100 0.051172 419330 423136
Here, the percolation is being assessed every 20 cycles. One can observe that during the first 100 cycles of hydration, the water-filled capillary porosity remains highly connected.
The optional sixth file, percset.out, provides similar percolation results, but for the percolation of "total solids". This is useful to assess the setpoint as the cement hydrates. For the assessment of setting, "total solids" refers to the initial cement clinker phases (C3S, C2S, C3A, and C4AF) along with the C-S-H and ettringite hydration products. It is thus assumed that setting is due to the building up of bridges of C-S-H and/or ettringite between neighboring cement clinker particles. This file contains the same four columns as percpore.out, but the last two are the tabulations for "total solids" instead of water-filled capillary porosity. An example output file is as follows:
2 0.000994 0 484081 2 0.000994 0 484081 2 0.000994 0 484081 4 0.002199 0 486171 4 0.002199 0 486171 4 0.002199 0 486171 6 0.003494 0 488213 6 0.003494 0 488213 6 0.003494 0 488213 8 0.004646 0 490239 8 0.004646 0 490239 8 0.004646 0 490239 10 0.005705 0 492191 10 0.005705 0 492191 10 0.005705 0 492191 12 0.006752 0 494061 12 0.006752 0 494061 12 0.006752 0 494061 14 0.007805 0 495780 14 0.007805 0 495780 14 0.007805 0 495780 16 0.008887 0 497544 16 0.008887 0 497544 16 0.008887 0 497544 18 0.009978 125404 499339 18 0.009978 0 499339 18 0.009978 0 499339 20 0.011002 136632 501114 20 0.011002 144049 501114 20 0.011002 109638 501114 22 0.012058 168441 502960 22 0.012058 197793 502960 22 0.012058 123816 502960 24 0.013066 184665 504638 24 0.013066 227537 504638 24 0.013066 141164 504638 26 0.014084 271832 506333 26 0.014084 261729 506333 26 0.014084 264142 506333 28 0.015076 323770 507952 28 0.015076 318342 507952 28 0.015076 324153 507952 30 0.016026 344087 509449 30 0.016026 337642 509449 30 0.016026 340686 509449
Here, it can be observed that "setting" (connected fraction > 50 %) occurred when approximately 1.5 % of the initial cement phases had hydrated, in general agreement with experimental observations [11].
The optional seventh file, partlist.hyd, contains the information on the degree of hydration of each individual cement particle (greater than one pixel in diameter) within the 3-D microstructure. Each time this file is appended, the new first line contains the number of cycles of hydration that have been completed and the current degree of hydration on a mass basis. Subsequent lines contain four columns: the particle ID (100, 101, ...), the initial number of cement pixels in the particle, the current number of cement pixels in the particle, and the calculated volumetric degree of hydration for this particle. The particle IDs start with 100, because within the program genpartnew.c, lower value IDs are used to signify aggregate, etc. The particle hydration data could be used to analyze the dependence of degree of hydration on particle size, as it is well known that while the smaller cement particles (< 10 µm) hydrate completely within 28 days or so [15], the inner portions of larger particles may remain unhydrated indefinitely. Two small portions of an example output file are as follows:
100 0.050533 100 22575 22434 0.006 101 15515 15402 0.007 102 12893 12737 0.012 103 10395 10322 0.007 104 8217 8151 0.008 105 8217 8138 0.010 106 6403 6321 0.013 107 6403 6329 0.012 108 4945 4861 0.017 109 0 0 0.000 110 4945 4912 0.007 111 3695 3635 0.016 112 3695 3655 0.011 113 3695 3646 0.013 114 3695 3647 0.013 115 2553 2520 0.013 116 0 0 0.000 117 2553 2516 0.014 118 2553 2514 0.015 119 2553 2522 0.012 . . . 5100 19 18 0.053 5101 19 18 0.053 5102 19 17 0.105 5103 19 18 0.053 5104 19 19 0.000 5105 19 18 0.053 5106 19 18 0.053 5107 19 19 0.000 5108 19 18 0.053 5109 19 19 0.000 5110 19 16 0.158 5111 19 18 0.053 5112 19 15 0.211 5113 19 19 0.000 5114 19 17 0.105 5115 19 19 0.000 5116 19 18 0.053 5117 19 17 0.105 5118 19 19 0.000 5119 19 16 0.158 5120 19 17 0.105
Here, the top line indicates that after 100 cycles of hydration, the mass basis degree of hydration was about 0.05. Subsequent lines indicate that the individual particles have volume-based degrees of hydration between 0.006 and 0.017 for the larger particles (IDs 100 to 118) and generally between 0.053 and 0.211 for the smaller particles (IDs 5100 to 5120), consistent with the statement above that the smaller particles usually hydrate more completely than the larger ones. The particles whose last three columns are all zeros (e.g., 109 and 116 in the above list) indicate calcium sulfate particles (that contain none of the four cement clinker phases on which degree of hydration is based).
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