Properties and hydration products of lightweight and expansive cements Part I

Organic/inorganic bioactive materials part IV: In vitro assessment of bioactivity of gelatin-calcium phosphate silicate/wollastonite hybrids

“…The most important future in the obtained results is the relation between FTIR and EDS for the prepared Transmittance Wavenumber, cm [48,49]. In our case, the absorption band, centered at 1412 cm -1 (Fig.…”

Influence of cement and expansive additive types in the performance of self-stressing and self-compacting concretes for structural elements

“…Therefore, when using CEM I cement, a higher efficacy of the expansive additives based on CaO can be expected. This better performance must be likely related with the fact that the ettringite formation reactions need a larger water quantity to obtain almost the same expansion at equal doses [11] and in this study the water amount was the same for all the cases and there was not any water added during curing. Moreover, it has been reported that the ettringite crystallization principally takes place in the large pores and capillaries due to its much greater molar volume compared to the calcium hydroxide, but the products of hydroxide expansive additives fill the porous structure, crystallizing in the fine pores of the cement matrix [11].…”

“…For instance, when concrete is heavily restrained by the steel action, such as dense rebar reinforcement or concrete confined in steel tubes, large early tensile stresses can develop before concrete reaches its full tensile strength and cracking appears. In these cases, pre-stressing of the concrete can compensate these weaknesses and, in this sense, the use of self-stressing concretes (the concrete member is pre-stressed by chemical stress) is a good alternative [1,[4][5][6][7][8][9][10][11][12][13][14]. http However, there are many parameters to consider that influence the performance of expansive concretes, such as curing conditions, expansive additive type and dosages, concrete composition, aggregate type, w/c ratio, etc.…”

“…http However, there are many parameters to consider that influence the performance of expansive concretes, such as curing conditions, expansive additive type and dosages, concrete composition, aggregate type, w/c ratio, etc. [1,[5][6][7][9][10][11][12][13].…”

“…This is not a straightforward aspect considering that the mechanisms of expansion caused by ettringite or portlandite formation are not fully understood yet [11,12,[16][17][18]. Because of that, the present paper evaluates in depth the influence of different parameters in the self-compacting performance, the mechanical strength gain and the expansive regime, including the expansive additive type and content and the cement type (conventional or pozzolan cement, with different initial alumina content).…”