3 results about "Saturated-surface-dry" patented technology

The application provides a kind of iron tailings sand-containing machine-made sand concrete and a preparation method thereof, relates to the technical field of building materials and solid waste resource utilization, and includes obtaining iron tailings sand and machine-made sand, respectively detecting the fineness modulus, 0.075mm below particle content, water absorption and moisture content of the iron tailings sand, and the fineness modulus, stone powder content, water absorption and moisture content of the machine-made sand.The iron tailings sand-containing machine-made sand concrete and the preparation method thereof detect the performance state of the iron tailings sand and the machine-made sand, and combine saturated surface dry conversion, mixing water correction, pre-wetting correction, compound control and segmented mixing, etc.Processing flow, effectively regulate the preparation process of composite fine aggregate, thereby improving the mix proportion adaptability and preparation stability of the iron tailings sand-containing machine-made sand concrete, and reducing the workability fluctuation and performance instability caused by the difference in particle composition and water absorption characteristics of the two types of fine aggregate.

The application discloses a pre-mixed high-density compensation shrinkage wet spraying concrete yield shear stress regulation method and relates to the technical field of wet spraying concrete of hydraulic underground caverns, which comprises the following steps: S1, determining a yield shear stress target value τ0,targ in advance; and S2, according to the design strength and the slump, initially selecting the high-density compensation shrinkage wet spraying concrete water-binder ratio W / B, the cement mass mc, the silica fume mass msi, the expansive agent mass mexp, the water consumption mw, the water reducing agent mass mwr, the saturated surface dry state aggregate total mass ma and the mass fraction mPa,i of each particle size aggregate mixing ratio parameters. The application solves the wet spraying concrete mixing ratio production regulation and control problem oriented by the yield shear stress in the wet spraying construction process, realizes the wet spraying concrete production mixing ratio optimization adjustment based on the target yield shear stress, significantly reduces the rebound rate and the pipe blocking probability, and has obvious economic and social benefits.

The application discloses a kind of low additional water full recycled concrete based on recycled fine aggregate wet packing gradation optimization and preparation method thereof, belong to building material technical field.The application is classified into three intervals by natural gradation recycled fine aggregate, after pre-wetting to saturated surface dry state, the wet loose bulk density under each mass proportion combination is determined, and the highest density is selected as the optimal artificial gradation;60% of the saturated surface dry water absorption of all recycled aggregates is determined as additional water;cement, recycled fine aggregate, recycled coarse aggregate, initial water and water reducing agent are used to prepare by using the layered feeding process of "cement pre-mixing→ neat paste preparation→ coarse aggregate→ fine aggregate".The obtained concrete has a slump of 160-190mm, a 28-day compressive strength of 25-40MPa, good fluidity, can meet the construction requirements of conventional concrete structure, and does not need chemical modification, low cost, suitable for building solid waste large-scale utilization.