I-Cal 4000 HPC ("High Precision Calorimeter")는 4 채널 등온열량계로써, 최대 125ml의 시멘트, 모르타르 및 콘크리트 샘플에 대한 특성의 R&D와 검사 작업 뿐만 아니라 시멘트, 콘크리트 생산에 필요로 하는 일상적인 품질 테스트를 포함하여 다양한 분야에 적용 할 수 있습니다. I-Cal 4000 HPC는 가변 레퍼런스 (variable reference)를 사용하므로, 광범위한 시료의 수화열 측정이 가능한 고성능 기기입니다. 온도를 매우 정밀하게 제어하는 I-Cal 4000 HPC는 최대 28일 동안 측정을 지속할 수 있습니다. I-Cal 4000 HPC는 ASTM C1679, ASTM C1702, ASTM C563, EN 196-11 규격을 완벽히 따릅니다.
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- ASTM C1679 "Standard Practice for Measuring Hydration Kinetics of Hydraulic Cementitious Mixtures Using Isothermal Calorimetry"
- ASTM C1702 "Standard Test Method for Measurement of Heat of Hydration of Hydraulic Cementitious Materials Using Isothermal Conduction Calorimetry"
시멘트 수화 반응에 의해 생성된 heat flow를 측정하는 정밀 센서와 함께 시료 주변 온도는 Calmetrix의 소프트웨어 인터페이스에 의해 컴퓨터 제어됩니다. 다만, I-Cal HPC 열량계 제품군은 외부 조건에 대한 감도를 최소화하기 위한 똑똑한 디자인으로 차별화되었습니다. 이는 보다 일관된 결과를 제공할 뿐만 아니라 어떠한 실내 온도 환경에서도 강력한 성능과 재현성 측면에서도 확연한 베네핏, 냉방 시설이 없는 현장 실험실의 비용 절감을 의미합니다.
Example:
analyze performance of blends with high cement substitution levels (Applicable Instruments: any I-Cal instrument)
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Calorimetry is a convenient tool to assess the performance of blended cements. In this example, we are studying three blends, with 50%, 60% and 70% slag (green, yellow and red, respectively). The top left graph shows power normalized by mass of cement. The narrow and more intense main peak of hydration is indicative of an issue. The upper right graph shows total heat of hydration also normalized by mass of cement. The overlapping green and yellow curves show that increasing slag from 50% to 60% does not disrupt the cement hydration reaction.
But the red curve is well below, indicating that the increase from 60% to 70% slag has a negative effect on cement hydration. This is likely attributable to sulfate depletion as aluminate glass present in the slag consumes sulfate in the cement to a point where it can no longer retard the aluminate reaction. The bottom graph shows heat of hydration (energy) by mass of total binder (cement + slag). Heat of hydration is closely correlated to strength gain, especially at early ages. Therefore, the gradually decreasing energy is expected, as higher cement substitution rates are known to have a decreasing effect on early strength gain.
Applications:
I-Cal 4000 HPC는 시멘트, 콘크리트 특성에 대한 R&D 및 검사 업무 뿐만 아니라 시멘트, 콘크리트 생산 시 일상적인 QC 요구 사항에 따른 시험에 적합합니다. 일반적인 용도는 아래와 같습니다.
- ASTM C1702에 따른 수화열 (heat of hydration) 측정
- 시멘트와 혼합물의 잠재적인 재료 비호환성 (material incompatibility) 검출
- admixture formulation
- shotcrete accelerator studies
- 황산염최적화 (sulfate optimization)
- 혼합물 또는 다른 재료 함량의 변화에 대한 민감도 테스트 (sensitivity test)
- 수화열 측정 그래프를 이용한 수축 강도 (compressive strength) 예측
- 열적인 균열 예측 (thermal crack prediction)을 위한 활성화 에너지 (activation energy) 결정
- 온도 변화에 대한 감도 테스트
- 혼합 설계 최적화 및 통계 성능 분석
- test temperatures of more than 50 °C (up to 70 °C), e.g. for studies of delayed ettringite formation
- "Delayed ettringite 형성"에 대한 연구가 가능한 측정 온도 (예, 70 °C)
- 보충 시멘트질 재료의 특성 연구
- 7일 이하의 경화 시간을 갖는 실험 연구
Example:
sulfate optimization using the depletion peak (Applicable Instruments: any I-Cal instrument)
Many issues of adverse interaction between admixtures and other materials in concrete are caused by sulfate imbalance. With an isothermal calorimeter, it is easy to optimize sulfate forms and total SO3 for cements, both with and without admixtures in the mix. This example shows the effect of SO3 addition to a cement without admixture on the rate of the hydration reaction.
The Cement “as is” (green) has no visible sulfate depletion peak. Addition of sulfate in (0.25%, 0.5% and 1% in the yellow, red and blue curves) moves the sulfate depletion to a later time relative to the main peak. The total energy increases until an optimum is reached, likely inbetween the red and blue curves.
When to consider an I-Cal 4000 HPC
I-Cal 4000 HPC is the right isothermal calorimeter for experiments that have the following characteristics:
- curing at any temperaure, and up to 70 °C when needed
- test durations of any length up to 7 days
- Heat of hydration testing as per ASTM C1702
Specification:
- Number of test channel: 4
- Operating temperature range: 5 to 70℃ (41 to 158℉)
- Temperature stability:: Better than ± 0.02 ℃ in laboratory conditions
- Software compatibility: Calcommander on Window 7, 10 or later
- Maximum recommended test duration: 28 days
- Sample size: up to 125ml /~340g (12oz.)
- Baseline over 74 hours: Drift, less than 0.05 µW/gh, Random noise, less than ± µW/g
- Dimensions: L55 cm x W42 cm x H56 cm
- Weight: 47 kgf
- Operating voltage: 110 ~ 240VAC, 50/60Hz
I-Cal 4000 HPC ("High Precision Calorimeter") is a 4-channel Isothermal Calorimeter. Like all Calmetrix I-Cal isothermal calorimeter models, I-Cal 4000 HPC features a sample size of up to 125ml, which can be used for multiple applications, including R&D and Investigative work on cement, mortar and concrete properties as well as daily QC needs in cement and concrete production. Variable reference cells make I-Cal 4000 HPC a versatile equipment, making it possible to test cement, mortar and real concrete, or other materials of various types and sample sizes. I-Cal 4000 HPC's tight temperature control is usitable for tests lasting up to 28 days.
I-Cal 4000 HPC is fully compliant with ASTM C1679, ASTM C1702, ASTM C563 and EN 196-11.
The ambient temperature around the samples is computer-controlled by Calmetrix's software interface, with precision sensors measuring the heat flow generated by the cement hydration reaction. But the I-Cal HPC line of calorimeters distinguishes itself by its clever design to minimize sensitivity to outside conditions. This means more consistent results, but also a robust performance even in a non-air conditioned environment, a definitive benefit in terms of reproducibility, and cost savings for field laboratories or rooms that are not tightly air-conditioned.
