Engineering analysis + design software

Software Option for Plus versions

Heat of Hydration

The Heat of Hydration software option allows for modelling the heat of hydration of concrete for a variety of cement types. Effects due to the addition of fly ash and ground granulated blast furnace slag can also be included. When used with the Nonlinear, Dynamic, and Thermal software options the heat of concrete hydration can be computed during a thermo-mechanical coupled analysis, with the temperatures and degree of hydration used by a structural analysis to determine a range of time and age-dependent effects.

In summary

LUSAS has long been known for its advanced analysis capabilities, with a concrete cracking and crushing material model developed over many years in collaboration with top researchers in the field. Using the time-dependent creep and shrinkage concrete material model allows for better assessment of existing concrete structures and better predictions for concrete placed quickly or adjacent to existing material.

For early age concrete, hygro-thermal analyses allow the determination of heat of hydration across a body of concrete, taking into account the availability of water for the exothermic reaction with time, based on the concrete mix, shape, exposed faces, insulated surfaces, environmental conditions etc. This avoids the use of "typical" heat generation curves, although these can still be drawn upon for comparison purposes.

When a hygro-thermal analysis is coupled with a structural or "mechanical" analysis, the cracking, crushing, creep and shrinkage capabilities of LUSAS can be employed.This allows the determination of time- and age-dependent deformations, stresses, crack-widths and more, working to - and beyond the scope of - international Codes of Practice.

In detail

The Heat of Hydration software option allows for 2D/3D modelling of coupled thermal-mechanical behaviour of concrete due to its curing, and can also allow for inclusion of formwork and other materials that might act as insulators. The analysis results in thermally induced strains that can be used to calculate crack widths and crack patterns. Heat of Hydration analysis can be undertaken on mass or reinforced concrete with detailed geometric modelling of reinforcement within the concrete section being possible. The user has full control over the ambient and casting temperatures at the start of the analysis and can also allow for fluctuations in temperature. The internal inclusions of artificial cooling or heating can be done at discrete locations in a 2D analysis or along pipe lines in a 3D analysis. Results from LUSAS have been validated against academic research and also against a third party heat of hydration program.

Heat of hydration example

In the simplistic example shown right, a cube of concrete is modelled with an 8x8x8 mesh of HF8/HX8 elements and the concrete curing process is simulated. Temperatures due to the heat of hydration can be obtained by examining the hourly timestep results.

From the half-model results it can be seen that the greatest temperature differential occurs at 34 hours. 

A structural analysis using a concrete cracking model based upon mechanical properties for this time interval is then carried out and cracks can be observed when differential expansion is enough to cause principal stresses that lead to material failure.

Animation of temperature change in mid-section of concrete block

Crack planes at 35 hours

Maximum principal stresses at 35 hours

Hygro-thermal analysis of a dam

For the staged construction of a dam, the effects that formwork and environmental conditions have on the curing concrete can be examined and The temperatures and stresses for each time step for each construction stage can be obtained.:

Staged construction model Modelling formwork during a stage

Temperature Stress

Graphs of results such as the changing of concrete temperature over time, shrinkage and thermal strains, or water distribution, and more can be obtained:

And calculated crack widths for each time step in each construction stage, both internally and externally, can be visualised:

Dependent software options

Use of the Heat of Hydration software option requires the following other software options to be accessible.

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Any modelling, design and analysis capabilities described are dependent upon the LUSAS software product, version and option in use.