Behaviour of Ca(OH)2 in polymer modified mortars

Effect of Styrene Butadiene Ratio on Mechanical Properties of Concrete Mixture

“…These groups, ionized in the highly alkaline environment of fresh mortar, tend to interact with Calcium ions from the cement hydrates, which generally results in improved stability of the polymer and adhesion of the polymer-modified mortar to existing substrates [12][13][14] . Figure 10 illustrates the possible interactions between X-SBR particles with cement grains or cement hydrates, which is consistent with the conclusion that polymer modifier absorbs calcium on the formed polymer film and thus reduces the formation of Portlandite with the increase of polymer content in mortar [15] . On the other hand, at higher polymer=cement ratios, the X-SBR particles distributed 1338 more homogeneously in the mortar and the microstructure of the mortar became denser and more refined.…”

Analyses of microstructural properties of VA/VeoVA copolymer modified cement pastes

“…These results are in line with those shown by the studies of reference 10, which employed similar proceedings. The decrease of portlandite formation by addition of the cement modifiers can be both the consequence of lower cement hydration and a possible chemical interaction between groups from alkaline hydrolyses of polymers and hydration products of portland cement [1,9,10] . As shown in reference [13] , some polymers that contain vinyl acetate group can suffer hydrolysis when dispersed in alkaline medium.…”

“…• 100 °C: dehydration of pore water • 100 -300 o C: different stages of C-S-H dehydration • ~500 °C: dehydroxylation of Ca(OH) 2 • ~700 °C: decarbonation of CaCO 3 As explained above, polymer modification reduces the quantity of Ca(OH) 2 formed in the mortars [10] . This work reports results of investigations in which methods of thermal analysis were applied to evaluate the effects of polymer modification on the hydration process of Portland cement by estimating Ca(OH) 2 content and calcium hydrates content.…”

Studies on γ-irradiated polymer–nano calcined clay blended cement mortar composites

“…The oxide composition of OPC and NCC used in this investigation are shown in Table 1. Polyvinyl alcohol (PVA) powder with particle size 0.0449 mm, degree of polymerization (1700-1800), viscosity (25)(26)(27)(28)(29)(30)(31)(32), hydrolysis (mole%) (98-99), volatiles (max 5%) and pH value of water solution (5-7) was obtained from El-Gomhoria Company (Egypt).…”

“…XRD results show an important peaks of Ca(OH) 2 around 18.1, 34.2 and 47.1 (2u). It has been reported that, the peak intensity in the region of 2u = 18.18 considered as a measurement of the intensity of Ca(OH) 2 for the comparison between the samples [26]. It can clearly seen that the lowest intensity of Ca(OH) 2 peak around 2u = 18.18 for the irradiated PVA-NCC-cement mortar composite, this may be attributed to chemical reactions between the composite constituents during irradiation process as shown in Figs.…”