Influence and Mechanism of NO2-LDH on Effect of Superplasticizer

Abstract:

Nitrite intercalation hydrotalcite（NO₂-LDH） was prepared by roasting and reduction method， and its effect on adsorption， dispersion and enhancement of superplasticizer were studied. The results show that the layer spacing and crystallinity of the NO₂-LDH are slightly lower than that of protocarbonate type Mg-Al hydrotalcite. There is anion exchange between NO₂-LDH and superplasticizer， which reduces the adsorption and dispersion effect of superplasticizer. The decreasing degree of dispersion effect of superplasticizer increases with the increase of NO₂-LDH content. NO₂-LDH has no obvious effect on the flexural strength of mortar mixed with superplasticizer， but the compressive strength is slightly increased. The effect of NO₂-LDH on the dispersion of naphthalene superplasticizer is greater than that of polycarboxylic acid superplasticizer.