It discloses cement grinding aids prepared with waste antifreeze which comprises the following components in parts by weight: 20-75 parts of pretreated waste antifreeze, 5-40 parts of alkanolamine, 1-5 parts of acid solution, 3-12 parts of saccharide and 15-50 parts of water. The pretreated waste antifreeze is prepared by adding an alkaline solution into waste antifreeze to regulate the pH value, adding a flocculant, and stirring and standing; separating upper-layer oil, and then filtering to remove flocculent precipitates, thus obtaining a clear mixed solution.

It discloses cement grinding aids prepared with waste antifreeze which comprises the following components in parts by weight: 20-75 parts of pretreated waste antifreeze, 5-40 parts of alkanolamine, 1-5 parts of acid solution, 3-12 parts of saccharide and 15-50 parts of water. The pretreated waste antifreeze is prepared by adding an alkaline solution into waste antifreeze to regulate the pH value, adding a flocculant, and stirring and standing; separating upper-layer oil, and then filtering to remove flocculent precipitates, thus obtaining a clear mixed solution.

It discloses cement grinding aids prepared with waste antifreeze which comprises the following components in parts by weight: 20-75 parts of pretreated waste antifreeze, 5-40 parts of alkanolamine, 1-5 parts of acid solution, 3-12 parts of saccharide and 15-50 parts of water. The pretreated waste antifreeze is prepared by adding an alkaline solution into waste antifreeze to regulate the pH value, adding a flocculant, and stirring and standing; separating upper-layer oil, and then filtering to remove flocculent precipitates, thus obtaining a clear mixed solution.

A solidification and setting accelerator for hydraulic binders, in particular for shotcrete/gunite or sprayed mortar, comprises sulfate, aluminum and at least two chemically distinct organic acids, each of which contains at least one hydroxy group in addition to at least one acid group, the combined maximum content of the at least two organic acids being 1 wt % in relation to the total weight of the accelerator.

A solidification and setting accelerator for hydraulic binders, in particular for shotcrete/gunite or sprayed mortar, comprises sulfate, aluminum and at least two chemically distinct organic acids, each of which contains at least one hydroxy group in addition to at least one acid group, the combined maximum content of the at least two organic acids being 1 wt % in relation to the total weight of the accelerator.

A solidification and setting accelerator for hydraulic binders, in particular for shotcrete/gunite or sprayed mortar, comprises sulfate, aluminum and at least two chemically distinct organic acids, each of which contains at least one hydroxy group in addition to at least one acid group, the combined maximum content of the at least two organic acids being 1 wt % in relation to the total weight of the accelerator.

A solidification and setting accelerator for hydraulic binders, in particular for shotcrete/gunite or sprayed mortar, comprises sulfate, aluminum and at least two chemically distinct organic acids, each of which contains at least one hydroxy group in addition to at least one acid group, the combined maximum content of the at least two organic acids being 1 wt % in relation to the total weight of the accelerator.

A combination of retarders and regulators for hydration reaction of cementitious binders including clinkers based on Ye'elimite. Set retarders are calcium complexing agents, consisting of sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, phosphates, phosphonates, borates and amines. Regulator general formula (I) is ##STR00001##
where M is H, NH.sub.4 or chosen from monovalent or divalent metal of groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of periodic table of elements, where M is a divalent metal, a second equivalent of RSO.sub.3 is present, and M is chosen from group consisting of H, NH.sub.4, Li, Na, K, MgX, CaX, or NiX with XRSO.sub.3, and R is chosen from H, NH.sub.2, OH or from hydrocarbon chain with 1-18 C atoms which may be substituted by N and/or O and/or which may be linear or branched and/or which contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic moieties.

A strengthening concrete admixture for the production of high-strength concrete products is provided. The strengthening concrete admixture comprises water; a set retarder comprising a salt of gluconic acid; one or more set accelerators; one or more hardening accelerators; and at least one stabilizing agent. Incorporation of the strengthening admixture in a cement mixture enhances both early and late age strength development and allows for sustainable and more energy efficient construction practices.

Disclosed are a reinforced magnesium substrate and a composite board with the same. The reinforced magnesium substrate includes the following components in parts by weight: 240-280 parts of magnesium oxide, 172-192 parts of wood fiber, 1.3-3.5 parts of citric acid, 1.3-3.5 parts of phosphoric acid, 1.3-3.5 parts of sodium sulfate, 90-120 parts of magnesium sulfate and 109-130 parts of water. The composite board with the reinforced magnesium substrate includes the reinforced magnesium substrate, wood board layers and a wear-resistant layer. The reinforced magnesium substrate is configured as a board core of the composite board; the wood board layers are arranged on the two sides of the reinforced magnesium substrate respectively; and the wear-resistant layer is arranged on at least one wood board layer and relatively fixed with the wood board layer.