Cement concrete isothermal calorimeter

Background: Isothermal calorimetry in cement and concrete testing

The isothermal calorimetry method characterizes the reaction rate of cementitious materials by the amount of heat released per unit time during the hydration process. Due to the importance of reaction rate on the workability (such as workability, setting time, and early strength development) of cementitious slurries, calorimetry is widely used in the development of new cementitious materials and composite materials, quality control, and the study of the effects of different chemical additives and cementitious material compositions on performance.

I-Cal 8000HPCHigh precision professional calorimeter for cement/concrete

I-Cal 8000HPCCement concrete isothermal calorimeterIt is an 8-channel isothermal calorimeter that can be used to test cement paste, mortar, and even concrete. Testing concrete is particularly important for detecting the interaction between composite admixture molecules and cementitious materials. Draw the hydration heat curve when the ambient temperature around the sample remains constant. Through software interface with feedback loop, temperature can be easily set to ensure control. And high-precision sensors can measure the heat flow generated by the hydration of cementitious materials in concrete. The I-Cal 8000HPCC uses Calmetrix's dedicated variable reference sample to adjust the reference sample size of each sample channel, thereby improving flexibility and accuracy, while the configuration of a single channel reduces mutual interference between channels. Compliant with ASTM C1679 and ASTM C1702 standards, it can be used for both short-term and long-term hydration heat measurements.

The working principle of shotcrete quick setting agent is to accelerate the formation of hydrated calcium sulfoaluminate in cement hydration products, so the reactivity of aluminate and sulfate phases in cement is particularly important. The use of I-Cal 8000HPC is currently a suitable method for evaluating the activity of cement minerals and the performance of accelerators. For the same sprayed concrete quick setting agent, due to the varying reactivity of aluminum and sulfate reactions within different cements, please use the same cement when evaluating the performance of the quick setting agent.

The above figure shows the study on the influence of different dosages of shotcrete accelerators on their performance using an isothermal calorimeter. The green curve represents the sample with a single retarder, while the four sets of curves from yellow to black show the heat release rate and curves of the sprayed concrete quick setting agent samples with mass fractions of 2%, 4%, 6%, and 8% after adding a quantitative retarder. It can be seen that the hydration main peak of each sample is advanced and the setting time is rapidly reduced after the addition of the rapid setting agent; There are significant differences in the effect of different dosages of accelerators, indicating that this accelerator has better performance.

Retrieve and analyze data generated by I-Cal using Calmmetrix's Calcommander software, which includes a comprehensive set of user-friendly tools. Calcommander includes software tools such as output reports, determination of activation energy, estimation of setting time, prediction of compressive strength, hydration heat testing, and sulfate optimization.

Isothermal calorimetry can be used to estimate the solidification time of materials, as the heat release rate of the heat release curve is related to physical test data obtained through standards such as ASTM C403. In the above figure, the green curve represents the mixture of Portland cement and effective water reducing agent, the yellow curve represents the mixture with 0.4% TEA added, and the red curve represents the mixture with 0.4% TIPA added. The proprietary I-Cal set software from Calmmetrix models the initial and final setting of each mixture, clearly demonstrating the impact of each admixture on cement. The use of calorimetry can greatly reduce the time, effort, and cost required for physical testing of condensation time. In addition, precise temperature control in isothermal calorimeter provides a simple method to ensure the reproducibility of results.

Scope of application
I-Cal 8000HPCCement concrete isothermal calorimeterIt is a high-precision cement concrete calorimeter with a large sample size, making it suitable for all applications of cement and concrete. Like other isothermal calorimeters from Calmmetrix, the main purpose of I-Cal 8000HPC is also for the research, development, and testing of concrete properties, as well as for daily quality management needs of cement concrete products.
The I-Cal 8000HPC is typically used to perform the following tasks:

• Predicting and estimating compressive strength or setting time

• Sensitivity testing under temperature changes

• Test the instability of sulfates and provide solutions

• Define the hydration heat of cement or cementitious materials (e.g. ASTM C1702)

• Optimize the mix design and select appropriate amounts of chemical and mineral additives

• Detect and eliminate potential incompatibility issues between materials and additives in the mixture slurry

• Testing the sensitivity of slurry properties to changes in additives or other raw materials

• Define activation energy to provide predictions for hydration degree, strength, and temperature cracks

The users of I-Cal 8000HPC are widely distributed in research institutions and cement concrete related enterprises such as cement production laboratories, universities, concrete producers, fly ash distributors, admixture manufacturers, and testing laboratories.