摘要:
A construction material composition includes a cross-linked starch derivative of a starch that is rich in amylopectin and has an amylopectin content greater than 85%.
摘要:
A variety of methods and compositions are disclosed, including, in one embodiment, a method of cementing in a subterranean formation, comprising: providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; activating the set-delayed cement composition; introducing the set-delayed cement composition into a subterranean formation; and allowing the set-delayed cement composition to set in the subterranean formation.
摘要:
Provided is a fiber reinforced cement based mixed material having high tensile strength and high toughness, the mixed material comprising a cementitious composition with fast development of early strength; a small hydration heat temperature; and a small shrinkage during curing. The fiber reinforced cement based mixed material contains 100 wt. parts of cement, 5-30 wt. parts of silica fume, 30-80 wt. parts of at least one pozzolanic material excluding the silica fume, 5-25 wt. parts of limestone powder, at least one chemical admixture, water, 70-150 wt. parts of aggregate having a largest aggregate diameter of 1.2-3.5 mm, and fibers, wherein at least some of the fibers comprise a fiber having asperities formed in the surface, the fiber having asperities being formed such that a ratio (h/H) of a depth h of each of recessed portions among the asperities to a smallest cross-sectional diameter H thereof is 0.05-0.8.
摘要:
Methods and compositions that protect cement compositions from corrosion, particularly from wet carbon dioxide, are provided. A soluble salt additive is provided to react with reaction products generated during the reactions that occur when cement is exposed to wet carbon dioxide. The soluble salt reacts to form an insoluble salt that forms a protective layer on the surface of the cement that protects it from further corrosion from exposure to wet carbon dioxide.
摘要:
The invention provides a process for the production of a cementious material. The process comprises mixing cement starting materials and a particulate healing agent to provide the cementious material. The healing agent comprises coated particles, wherein the coated particles comprise bacterial material and additive. The bacterial material is selected from the group consisting of a bacterium, a lyophilized bacterium and a bacterial spore of a bacterium. The present invention solves these problems, as (substantially leakage-proof) tablets containing the actual healing agent may neither interfere with either the workability of the liquid mixture (“cementious material”) nor negatively affect properties of either mixture or final material (hardened concrete), even when applied in large quantities. During crack formation in cementious based constructions, the particles also crack, and healing agent is released.
摘要:
A water retention agent for a cementitious composition, characterized in that it takes the form of a liquid aqueous suspension of at least one polysaccharide at a mass concentration of between 15 and 30% in an aqueous solution of a strong base salt, excluding ammonium salts, with an anionic strength of between 1.25 mol/L and 15 mol/L, having a pH greater than 9 and containing an attapulgite in micronized form and at least one non-phyllitic mineral powder, referred to hereafter as filler, which is chemically inert in the aqueous suspension and which has a grain size of between 0.1 and 100 micrometers, the aqueous suspension being stable at least in a temperature range of between 5° C. and 30° C. The water retention agent is suitable for increasing both the viscosity and the water retention capacity of cementitious compositions without affecting the spreading ability thereof.
摘要:
A method of producing cementitious mixtures containing fly ash as one of the cementitious components, under air entrainment conditions is described. The method involves forming a mixture comprising water, cement, fly ash, optionally other cementitious materials, aggregate, conventional chemical admixtures, and an air entrainment agent and agitating the mixture to entrain air therein. Additionally, at least one amine sacrificial agent is included in the mixture. The cementitious mixtures and hardened concretes resulting from the method and fly ash treated with sacrificial agent, or air entrainment agent/sacrificial agent combinations, are also described.
摘要:
A cementitious freeze-thaw damage resistant composition includes hydraulic cement, and coffee grounds particles having a volume-weighted mean particle size of from greater than 50 μm to about 2000 μm. A method for preparing a freeze-thaw damage resistant cementitious composition includes forming a mixture of water, hydraulic cement, and coffee grounds particles having a volume-weighted mean particle size of from greater than 50 μm to about 2000 μm. The coffee grounds particles act to increase the freeze-thaw durability of the cementitious material. A cementitious freeze-thaw damage resistant composition comprising hydraulic cement, and organic particles comprising at least one of coffee grounds particles, leaf powder particles, starch microcontainers, ground tea leaf particles, or cork powder particles.
摘要:
A powder including, in percentages by weight: (a) 94% to 99% of particles of at least one refractory material, the main constituent(s) of which are alumina and/or zirconia and/or silica; (b) 1% to 6% of a hydraulic cement; (c) 0 to 0.03% of organic fibers; (d) optionally, 0.075% to 1% of a surfactant; and (e) optionally, a setting accelerator, where the fraction of particles having a size below 40 μm being distributed, in percentages by weight relative to the weight of the powder, in the following manner: (1) fraction
摘要:
The invention relates to compositions and methods for modifying cementitious materials such as by reducing setting time. Polymer compositions of the invention are derived by polyetherifying mono-glycerols, optionally with alkylene glycols, to obtain polyglycerol homopolymers or copolymers, and then carboxylating the obtained polyglycerol homopolymers and/or copolymers with an organic acid having at least two carboxylic functionalities. The set retardation effect of the carboxylated-carboxylic polyglycerol polymer compositions in cementitious materials is reduced is compared to polyglycerol polymer not having the carboxylated-carboxylic groups, while its water reducing ability is maintained without loss of early compressive strength. Cementitious compositions and methods involving the carboxylated-carboxylic polyglycerol are also covered by the invention.