Takayuki Higuchi

• Doctor of Engineering
• General manager at Denka

Quick-hardening cement is used in urgent repair construction or in cold region to be hardened within a few hours and show high strength at early age. This type of cement consists of ordinary portland cement（OPC）, amorphous calcium aluminate and calcium sulfate. The main hydrate of this cement is ettringite（3CaO・Al2O3・3CaSO4・32H2O）, and this hydrate...

High-temperature carbonation of the lime in expansive additive（CSA）and the lime synthesized itself were evaluated. The CO2 in the lime synthesized itself increased continuously according to the treatment time. On the other hand, the increment of CO2 in CSA was almost finished in initial stage. The lime in CSA consisted of mono crystal, coated by Ca...

Application of high durable cementitious materials containing Low heat Portland cement（LHC）and expansive additive has been investigated for construction of the radioactive waste disposal facilities which is necessary for long term durability. But because the chloride ion cannot be fixed in this cement system, utilization of this is very difficult i...

An expansive additive containing lime(CaO), ye’elimite(3CaO・3Al2O3・CaSO4) and Anhydrite(CaSO4) was treated with high-temperature carbonation, and the effects of the treatment temperature and time on weathering resistance of the treated expansive additive were examined. After carbonation treatment between 400℃ and 800℃, the weathering was suppressed...

Inhibitory effect of Alkali Silica Reaction（ASR）by carbonationing and mortar, lowering pH was identified. Combined the effect that adds γ-C2S that feature carbonation activity, too, and considered. Dryness that concern carbonation curing considered for effect that effect on expansion behaviors of ASR, too. The aggregate which is not innocuous was u...

Aggregates account for approximately 7 of concrete volume unit of 10. For this, aggregates feature’s affecting properties and durability of concrete is known. Whereas, in, uses of industrial by-products including coal ash, fly ash, blast-furnace slag is facilitated. When baked clinker aggregates that is mainly composed of calcium silicate from indu...

Clinker fine aggregate should be utilized as aggregate in mortar or concrete, in order to achieve sustainable and environment friendly society. In this research, Ground granulated blast-furnace slag（GGBFS）and High alite cement（HAC）are used to improve the denseness and the resistance against chemical attack of mortar with clinker fine aggregate.In t...

This paper investigates pore structure of hardened cement paste containing microspheres. We compared the characteristics of its pore structure and pore structure by air entrained agent. The microsphere in this study was lightweight hollow sphere particle. Main component of the microsphere was acrylonitrile. The bulk density of microsphere was 0.13g...

Blast furnace cement paste having a high temperature history due to hydration heat shows the time dependent change of the thermal expansion coefficient and temperature strain remained in the shrinkage side after returning to ambient temperature. This shrinkage caused by temporal change of thermal expansion coefficient could increase the risk of the...

Quick-hardening cement is used in urgent repair construction or in cold region to be hardened within a few hours and show high strength at early age. The types of quick-hardening cement are divided into 2 roughly. One is Portland cement with quick-hardening additive, and another is special cement. We have studied about the basic properties of the m...

An expansive additive (CSA) containing lime (CaO), ye'elimite (3CaO·3Al2O3·CaSO4) and anhydrite (CaSO4) was treated with high-temperature carbonation, and used to make mortar samples for expansion tests. After 1 day, the mortar made with the CSA which underwent high-temperature carbonation (treated CSA) expanded to a lesser degree than the mortar m...

A new ecological concrete has been developed which utilizes CO2 emitted from a power plant and which can achieve CO2 emission levels below zero. This ecological concrete is named CO2-SUICOM (CO2 Storage under Infrastructure by Concrete Materials). This concrete is based on two typical features. One is using a special additive (the dicalcium silicat...

Ettringite quicklime complex expansive additive was treated with high-temperature CO2 gas in different condition and mixed with mortar, the physical properties and pore structure of the mixture were then evaluated. The expansion of mortar was reduced by the first day according to the carbonation time, but significant expansion was observed by the s...

A process for producing the alumina fiber aggregate which, when examined by the electron microscope method, gives a frequency distribution regarding number of fibers, wherein the number of fibers having a fiber length of 50-200 μm is 70% or more (including 100%), the number of fibers having a fiber length smaller than 50 μm is 30% or less (includin...

The effect of mineral additions based on calcium aluminates on the hydration mechanism of ordinary Portland cement (OPC) was investigated using isothermal calorimetry, thermal analysis, X-ray diffraction, scanning electron microscopy, solid state nuclear magnetic resonance and pore solution analysis. Results show that the addition of a calcium sulf...

The properties of cement quick-hardening additive are influenced depending on the quality of cement used. However, little is known concerning the influences of miner constituents on the properties of cement additives. One of miner constituents contained in cement is an alkali compound. In this report, we have studied about the influences of alkali...

If the calcium hydroxide by-product and the quartz rock with comparatively high purity are selected, 2CaO・SiO2（C2S） can be obtained because of burning the rotary kiln. The scorch point temperature was 1,450℃. Moreover, even if a special operation was not done during cooling, C2S was able to be obtained. The amount of the CO2 emission when C2S was m...

Clinker fine aggregate should be utilized as aggregate in mortar or concrete, in order to achieve sustainable and environment friendly society. In this research, densification of mortar by utilizing clinker fine aggregate is investigated. The self healing performance of clinker fine aggregate mortar with short fiber is also investigated after intro...

Ettringite quicklime complex expansive additive was treated with high-temperature CO2 gas and mixed with mortar. The physical properties of the mixture were then evaluated. The expansion deformation of mortar was reduced by the first day of the material age, but significant expansion occurred from the first day of the material age, and an increase...

Portland cement (OPC) with mineral additions based on CaO, SO 3 and Al 2 O 3 are being used in increasing amounts in both concrete practice and special applications as rapid hardening cement. The rapid hardening component used in this study is an amorphous calcium aluminate (ACA) with a composition close to C 12 A 7 blended with anhydrite. Results...

The precipitates in cracks in an actual utility concrete pole exhibiting self healing which had been in service for 34 years in a freezing and thawing environment were analyzed and the mechanism of self healing was discussed. CaCO3 was observed at the surface of the pole, and it was guessed from the condition of precipitation that water accumulated...

It was found that the self-compacting concrete added with the slowly cooled blast furnace slag powder has a better property of fluidity retention than the self-compacting concrete added with the granulated blast furnace slag powder or the lime stone powder. As for the mortar added with slowly cooled blast furnace slag powder, the greater the Blaine...

Fly ash cement prepared from high early strength cement (HPC) and fly ash (FA) was proposed and its ecological evaluation was performed. It has the following characteristics. Compared to ordinary portland cement (OPC), it has a shorter set time and has similar hardening characteristics to those of HPC. Its early strength up to age 7 days is higher....

Na-2-mica of the ideal composition of Na2Mg6Al2Si6O20F4·xH2O was prepared from a mixture of NaF, magnesium nitrate, SiO2 and calcined kaolinite (the latter serving as a cost-effective aluminosilicate source) at 800°C and was found to excel in Sr removal from solutions at room temperature. This mica was characterized by powder X-ray diffraction (XRD...