Topic
Cement
About: Cement is a research topic. Over the lifetime, 68440 publications have been published within this topic receiving 829356 citations.
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TL;DR: A correlation of features along the line T(1) = 4T(2) provides strong supportive evidence for the surface diffusion model of (1)H nuclear spin relaxation in cements and for a multimodal discrete pore size distribution.
Abstract: We report the first nuclear magnetic resonance NMR two-dimensional correlation T1-T2 and T2-T2 measurements of hydrating cement pastes. A small but distinct cross peak in the two-dimensional relaxation spectrum provides the first direct evidence of chemical exchange of water between gel and capillary pores occurring over the first 14 days of hydration. A correlation of features along the line T1=4T2 provides strong supportive evidence for the surface diffusion model of 1 H nuclear spin relaxation in cements and for a multimodal discrete pore size distribution. Differences in detail of the results are reported for white cement paste and white cement paste with added silica fume. Both the method and the theory presented can be applied more widely to other high surface area materials with other reactive surface areas.
291 citations
TL;DR: In this paper, the authors present four innovative utilizations of calcium sulfoaluminate (CSA) cement: development of concrete with high early strength: 40 MPa, 6 h after its preparation, and higher than 55 MPa after 24 h.
290 citations
TL;DR: In this paper, the authors investigated the hydration of a tricalcium silicate-based proprietary brand cement (Biodentine™) and a laboratory manufactured cement made with a mixture of trical calcium silicate and zirconium oxide (TCS-20-Z) and compared their properties to MTA Angelus™.
290 citations
Patent•
12 Jun 1992TL;DR: In this paper, a graphite aggregate is used to improve the thermal and electrical conductivity of the hardened cement slurry, which is useful for wellbores in high temperature service.
Abstract: A cement slurry is provided which is useful to cement wellbores in high temperature service. A high alumina cement is used. The density of the slurry is relatively low as a result of using a low density aggregate. In a preferred embodiment, the low density aggregate is graphite. The graphite additionally imparts a significantly improved thermal and electrical conductivity to the hardened cement.
290 citations
TL;DR: In this paper, the authors studied the self-healing potential of cement-based materials incorporating calcium sulfoaluminate based expansive additive (CSA) and crystalline additive (CA).
Abstract: This research studies the self-healing potential of cement-based materials incorporating calcium sulfoaluminate based expansive additive (CSA) and crystalline additive (CA). Mortar specimens were used throughout the study. At the age of 28 days, specimens were pre-cracked to introduce a surface crack width of between 100 and 400 μm. Thereafter, the specimens were submerged in water to create a self-healing process. The experimental results indicated that the mixtures with CSA and CA showed favorable surface crack closing ability. The optimal mix design was found to be a ternary blend of Portland cement, 10 wt.% CSA and 1.5 wt.% CA, by which a surface crack width up to about 400 μm was completely closed, and the rate of water passing was dropped to zero within 28 days. It was hypothesized that the amount of leached Ca 2+ from the matrix plays an important role on the precipitation of calcium carbonate which is the major healing product. The analyses showed that those specimens with CSA/CA additions released more Ca 2+ than that control specimen. Moreover, those specimens with additives had higher pH value which would favor calcium carbonate precipitation.
289 citations