摘要:
A solid mixture for the preparation of concretes with a mechanical strength after 28 days that is greater than or equal to 110 MPa comprising cement, calcareous aggregates and admixtures characterised by the fact that any additions with latent hydraulic activity are less than 5% by weight compared to the cement.
摘要:
A binder for self-compacting concrete includes, in dry weight of the-binder, 70 to 90% of Portland cement, 4 to 16% of calcium aluminate, 4 to 14% of calcium sulphate, an accelerator and a retarder, 0 to 2% of Ca(OH)2 and at least an additive with a water reducer. The calcium sulphate is in the form of anhydrite and the water reducer has at least a superplasticizer consisting of a water soluble or water dispersible organic compound, having at least an amino-di(alkylene-phosphonic) group and at least a polyoxyalkylated chain or at least one of its salts.
摘要:
A concrete mix, including: cementitious content between 25 and 200 kg/m3; fly ash content between 25 and 175 kg/m3; dirty sand with fine aggregates between 3% and 20%; water content between 150 I/m3 and 250 l/m3; and a chemical admixture comprising one or more components selected from the following: an acrylic, formaldehyde-free polymer-based admixture, modified in aqueous solution; a surfactant admixture configured to entrain micro air bubbles in concrete; and an organic polymer comprising hydrophilic groups for increasing the viscosity of the mixture.
摘要:
The invention relates to use of nano-fibrillar cellulose as an gas-entrainment stabilizer, which when used in cementitious materials, provides improved gas pore structure quality and/or stability and/or robustness with regard to water content variation. The invention further relates to a method for stabilizing gasentrainment of cementitious materials and to a method for providing cementitious material with improved air pore structure quality and/or stability and/or robustness with regard to water content variation.
摘要:
A low-density, high-strength concrete composition that is both self-compacting and lightweight, with a low weight-fraction of aggregate to total dry raw materials, and a highly-homogenous distribution of a non-absorptive and closed-cell lightweight aggregate such as glass microspheres or copolymer polymer beads or a combination thereof, and the steps of providing the composition or components. Lightweight concretes formed therefrom have low density, high strength-to-weight ratios, and high R-value. The concrete has strength similar to that ordinarily found in structural lightweight concrete but at an oven-dried density as low as 40 lbs./cu.ft. The concrete, at the density ordinarily found in structural lightweight concrete, has a higher strength and, at the strength ordinarily found in structural lightweight concrete, a lower density. Such strength-to-density ratios range approximately from above 30 cu.ft/sq.in. to above 110 cu.ft/sq.in., with a 28-day compressive strength ranging from about 3400 to 8000 psi.
摘要:
The invention relates to use of nano-fibrillar cellulose as an gas-entrainment stabilizer, which when used in cementitious materials, provides improved gas pore structure quality and/or stability and/or robustness with regard to water content variation. The invention further relates to a method for stabilizing gasentrainment of cementitious materials and to a method for providing cementitious material with improved air pore structure quality and/or stability and/or robustness with regard to water content variation.
摘要:
A heavy oil ash self-compacting concrete can include aggregate, heavy oil ash fines, water, and cement. The heavy oil ash can include more than 90% carbon, by weight. In an embodiment, the heavy oil ash self-compacting concrete can flow under its own weight and yet maintain a stable mixture consistency.
摘要:
A foamed concrete having a density from 100 to 800 kg/m3 including by mass relative to the total mass of the concrete: a cement; water; from 0.01 to 5% of a water-reducing agent, plasticizer or superplasticizer; from 0.45 to 5% of a foaming agent relative to the amount of water; from 0.01 to 5% of a water-soluble calcium salt; inorganic particles from 0.1 to 300 μm in size; the ratio of foaming agent to calcium salt being from 0.3 to 0.8; the foamed concrete including 10% or more by mass of slag.
摘要:
A foamed concrete having a density from 100 to 800 kg/m3 including by mass relative to the total mass of the concrete: a cement; water; from 0.01 to 5% of a water-reducing agent, plasticizer or superplasticizer; from 0.45 to 5% of a foaming agent relative to the amount of water; from 0.01 to 5% of a water-soluble calcium salt; inorganic particles from 0.1 to 300 μm in size; the ratio of foaming agent to calcium salt being from 0.3 to 0.8; excluding foamed concretes including 10% or more by mass of slag.
摘要:
The invention provides ‘thixotropy’ monitoring, by measuring the reversible, time-dependent reduction in viscosity occurring when concrete is subjected to mixing, and employs a mixing drum and conventional slump monitoring equipment as used on ready-mix trucks. In one embodiment, the drum is rotated until concrete is completely mixed; the speed is altered, such as by increasing it to a predetermined level; and the energy required to rotate the drum (ER) is monitored; the maximum (ER-MAX) and minimum (ER-MIN) values are recorded in computer memory; and these values are compared to pre-determined (target) values. Rheology factors (including viscosity, yield stress, and/or thixotropy) can be adjusted accordingly by adding liquid component(s) into the mix. This method, suitable for delivery of highly fluid concrete speed such as SCC, can involve transit and placement rheology targets during monitoring.