Abstract: The present invention discloses a method for preparing a concrete superplasticizer having a phosphorous acid group and a use of the concrete superplasticizer. The concrete superplasticizer having a phosphorous acid group according to the present invention is prepared by free radical copolymerization of a phosphorous-containing monomer A and a polyether macromonomer B. The concrete superplasticizer having a phosphorous acid group obtained in the present invention can effectively improve flowability of concrete and can retain good workability of concrete. The method is simple, economical and effective, and in particular, can be used for commercial mass production.

Abstract: Disclosed is a method for testing the self-drying effect of a cement-based material, capable of testing the change in humidity of the cement-based material after the final setting until the Id stage of adding water, so as to reflect the water consumption therein and the self-drying course. In the time period after the final setting of the cement-based material until the 1 d stage of adding water and forming, the dew-point temperature inside the cement-based material is tested, and then the relative humidity inside the cement-based material is calculated using a formula. The present invention can test the change in humidity of the cement-based material after the final setting until the Id stage of adding water, so as to reflect the internal water consumption therein and the self-drying course.

Abstract: Disclosed is a method for testing the setting time of a cement-based material: testing the capillary negative pressure of a non-bleeding cement-based material, with the time at which the capillary negative pressure reaches a threshold value A as the initial setting time, and/or the time at which the capillary negative pressure reaches a threshold value B as the final setting time, wherein threshold value A is 8-10 kPa, and threshold value B is 54-56 kPa.

Abstract: A slump retaining polycarboxylic acid superplasticizer. A weight average molecular weight of the superplasticizer is 20,000-80,000. The slump retaining polycarboxylic acid superplasticizer is prepared by performing polymerization reaction on a monomer A, a monomer B, a monomer C and a monomer D in an aqueous solution in the presence of a redox initiator, wherein a molar ratio of (the monomer A+the monomer B):the monomer C:the monomer D is 1:(3-8):(4-12), and a molar ratio of the monomer A to the monomer B is 1:(1-4).

Abstract: A slump retaining polycarboxylic acid superplasticizer. A weight average molecular weight of the superplasticizer is 20,000-80,000. The slump retaining polycarboxylic acid superplasticizer is prepared by performing polymerization reaction on a monomer A, a monomer B, a monomer C and a monomer D in an aqueous solution in the presence of a redox initiator, wherein a molar ratio of (the monomer A+the monomer B):the monomer C:the monomer D is 1:(3-8):(4-12), and a molar ratio of the monomer A to the monomer B is 1:(1-4).

Abstract: Disclosed is a method for testing the self-drying effect of a cement-based material, capable of testing the change in humidity of the cement-based material after the final setting until the Id stage of adding water, so as to reflect the water consumption therein and the self-drying course. In the time period after the final setting of the cement-based material until the 1 d stage of adding water and forming, the dew-point temperature inside the cement-based material is tested, and then the relative humidity inside the cement-based material is calculated using a formula. The present invention can test the change in humidity of the cement-based material after the final setting until the Id stage of adding water, so as to reflect the internal water consumption therein and the self-drying course.

Abstract: Disclosed is a method for testing the setting time of a cement-based material: testing the capillary negative pressure of a non-bleeding cement-based material, with the time at which the capillary negative pressure reaches a threshold value A as the initial setting time, and/or the time at which the capillary negative pressure reaches a threshold value B as the final setting time, wherein threshold value A is 8-10 kPa, and threshold value B is 54-56 kPa.