A S T U D Y O N T H E V A R I A T I O N O F C O M P R E S S I V E S T R E N G T H A N D P O R O S I T Y I N T H E C E N T E R O F M A S S I V E H I G H S T R E N G T H C O N C R E T E
Author(s):
Abstract:
An investigation was carried out to compare the effects of hydration heat and standard curing on the strength development and absorption water capacity of high strength concrete. In this regard, a temperature matched curing system (TMCS) was designed for simulation of the temperature rising of massive concrete within early stages. In this way, the freshly mixed concrete was cast into a cylindrical(150 $times$ 300−mm) mold and placed in a semi-adiabatic chamber. A thermocouple was dipped in the sample and the history of the temperature rising of the mixtures, via the designed system, was applied to the concrete samples, which were put inside a box to simulate hydration heat cured samples. Eight mixed proportions, with a water-binder ratio of 0.3, were prepared and the specimens were cured under both standard and heat curing conditions. Natural pozzolan, at 15% and 30%, and low-calcium fly ash, at 15% and 25%, by weight of cement, were used as a replacement for cement in the mixtures. Cement was also replaced by silica fume at three percentages of 5, 8 and 11. The results showed that the eak temperature of both natural pozzolan and fly ash specimens decreased compared to those made without pozzolan, whereas silica fume had no impact on the peak temperature of the mixtures. The results also declared that both early and later stages of compressive strength were seriously affected by the curing condition. Hydration heat curing, due to the rising temperature, had a positive impact on the later stage strengths of natural pozzolan and fly ash specimens, whereas heat curing diminished the later stage strengths of silica fume specimens. The later stage strengths decreased as the ercentage of silica fume increased. These findings revealed that care should be taken for utilization of silica fume in massive concrete structures. It is also concluded that a later stage of 91 days was more conservative for the specified strength of mass concrete. The results also showed that utilization of natural pozzolan, fly ash and silica fume diminished the absorption water capacity of the heat cured specimens, compared to those cured under standard conditions.
Keywords:
Language:
Persian
Published:
Sharif Journal Civil Engineering, Volume:28 Issue: 1, 2012
Page:
101
magiran.com/p1010266
دانلود و مطالعه متن این مقاله با یکی از روشهای زیر امکان پذیر است:
اشتراک شخصی
با عضویت و پرداخت آنلاین حق اشتراک یکساله به مبلغ 1,390,000ريال میتوانید 70 عنوان مطلب دانلود کنید!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی نامحدود همه کاربران به متن مطالب تهیه نمایند!
توجه!
- حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران میشود.
- پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانههای چاپی و دیجیتال را به کاربر نمیدهد.
In order to view content subscription is required
Personal subscription
Subscribe magiran.com for 70 € euros via PayPal and download 70 articles during a year.
Organization subscription
Please contact us to subscribe your university or library for unlimited access!