摘要:
In the preparation of aqueous cement compositions containing a plasticizer, such as an EO/PO polymer-containing plasticizer, or EO/PO comb polymer-containing plasticizer, and further containing clay, such as a smectite clay, which expands when in contact with water, the step of providing an agent operative to modify the clay whereby the plasticizer absorbing capability of the clay is reduced. In exemplary methods of the invention, the plasticizer is an EO/PO (e.g., oxyalkylene) plasticizer and preferably an EO/PO comb polymer, and the clay-activity-modifying agent may comprise an inorganic cation, an organic cation, a polar organic molecule capable of being absorbed by the clay, a clay dispersant (such as a polyphosphate), or a mixture thereof. For clay-activity-modifying agents which comprise a cation or a polar organic molecule, the agent is preferably added to the clay before water is introduced to the clay. For clay dispersant agents and some organic cations such as quaternary amines (which have a strong affinity for cationic exchange with the clay), the agent may be added before, during, or after water is introduced to the clay.
摘要:
In the preparation of aqueous cement compositions containing a plasticizer, such as an EO/PO polymer-containing plasticizer, or EO/PO comb polymer-containing plasticizer, and further containing clay, such as a smectite clay, which expands when in contact with water, the step of providing an agent operative to modify the clay whereby the plasticizer absorbing capability of the clay is reduced. In exemplary methods of the invention, the plasticizer is an EO/PO (e.g., oxyalkylene) plasticizer and preferably an EO/PO comb polymer, and the clay-activity-modifying agent may comprise an inorganic cation, an organic cation, a polar organic molecule capable of being absorbed by the clay, a clay dispersant (such as a polyphosphate), or a mixture thereof. For clay-activity-modifying agents which comprise a cation or a polar organic molecule, the agent is preferably added to the clay before water is introduced to the clay. For clay dispersant agents and some organic cations such as quaternary amines (which have a strong affinity for cationic exchange with the clay), the agent may be added before, during, or after water is introduced to the clay.
摘要:
The present invention relates to the use of polycationic compound in combination with a hydroxycarboxylic acid or salt thereof to enhance slump retention in cements and concretes having clay-bearing aggregates, wherein the clay otherwise absorbs or diminishes the dosage efficiency of polycarboxylate superplasticizers.
摘要:
The present invention is directed to an imidized polycarboxylic acid polymer useful as a cement admixture, to improved cement compositions containing said polymer and to a process of forming the same.
摘要:
The present invention relates to dispersants such as superplasticizers for hydratable cementitious compositions, and more particularly to methods for achieving variable degrees of longer slump life in concrete and mortar without loss of stability. This is achieved by using two admixture systems. The first admixture composition has multi-components for achieving initial-slump-enhancement, later-slump-retention, and limiting initial slump. The second admixture composition has the later-slump-enhancing component. Alternatively, conventional water reducers or superplasticizers can be employed initially, followed by the later-slump-enhancing admixture composition.
摘要:
The present invention relates to dispersants such as superplasticizers for hydratable cementitious compositions, and more particularly to methods for achieving variable degrees of longer slump life in concrete and mortar without loss of stability. This is achieved by using two admixture systems. The first admixture composition has multi-components for achieving initial-slump-enhancement, later-slump-retention, and limiting initial slump. The second admixture composition has the later-slump-enhancing component. Alternatively, conventional water reducers or superplasticizers can be employed initially, followed by the later-slump-enhancing admixture composition.
摘要:
The present invention relates to the use of polycationic compound in combination with a hydroxycarboxylic acid or salt thereof to enhance slump retention in cements and concretes having clay-bearing aggregates, wherein the clay otherwise absorbs or diminishes the dosage efficiency of polycarboxylate superplasticizers.
摘要:
The present invention is directed to an imidized polycarboxylic acid polymer useful as a cement admixture, to improved cement compositions containing said polymer and to a process of forming the same.