2026-06-07T05:26:07Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/210612026-02-03T11:31:21Zcom_10630_2254col_10630_37953

00925njm 22002777a 4500 dc Dapiaggi, Monica author Santacruz-Cruz, María Isabel author Cuesta-García, Ana María author Gómez-de-la-Torre, María de los Ángeles author Zea-Garcia, Jesus D. author García-Aranda, Miguel Ángel author 2021-03 At the microscale, C-S-H gels from alite, or neat Portland cements, has a Ca/Si ratio close to 1.80. At the nanoscale, C-S-H is described by a defective tobermorite structure which allows a maximum Ca/Si ratio close to 1.40. There is no agreement in the location of the extra 0.40 moles of Ca(OH)2 at the nanoscale. Atomistic modelling studies reported Ca(OH)2 species within the tobermorite interlayer space. Other works point toward a fine intermixing of defective tobermorite and nanoportlandite. Here, we have prepared a series of alite blended with silica fume and studied the pastes by several techniques including synchrotron pair distribution function (PDF). In the employed conditions, the C-S-H gel formed by the pozzolanic reaction has nearly the same local structure than the primary C-S-H gel. Furthermore, differential PDF points toward Ca(OH)2 excess having a local structure compatible with few-layer thick nanoparticles stretched along the c-axis. Cement and Concrete Research 143 (2021) 106405 https://hdl.handle.net/10630/21061 https://doi.org/10.1016/j.cemconres.2021.106405 Cemento Portland Cemento - Aditivos Local structure and Ca/Si ratio in C-S-H gels from hydration of blends of tricalcium silicate and silica fume