The invention provides methods and compositions for carbonation of a wet cement mix. The wet cement mix may be carbonated prior to addition of aggregates, admixture, SCM, and/or other components to produce a carbonated concrete mix. The methods and compositions may include high shear mixing of a cement or concrete mix, either during or before carbonation.

The present invention relates to an apparatus for producing rapid-hardening concrete and a method for producing same, the rapid-hardening concrete being produced by intermixing and dissipating air in normal concrete and adding an early-strength admixture thereto. With respect to forming rapid-hardening concrete, mixed concrete is formed by mixing in a large volume of air bubbles to be discarded, along with an early-strength admixture, to already mixed normal concrete, the early-strength admixture getting evenly dispersed therewithin by means of the ball bearing effect of the air bubbles, and when the mixed concrete is discharged, a rapid-hardening concrete is shotcreted while excess air contained in the mixed concrete is dissipated by means of high-performance air, the slump which was raised due to the large amount of air bubbles having been reduced to the slump range for normal concrete.

Hemihydrate and/or anhydrous Type III gypsum granules derived from wasted gypsum boards are fed into a flow path of an aqueous gypsum slurry containing dihydrate gypsum, are mixed with the gypsum slurry, and are fed into a deposition tank of dihydrate gypsum. The gypsum slurry is fed from an inlet of the flow path, and the hemihydrate and/or anhydrous type III gypsum granules derived from wasted gypsum boards are fed into the gypsum slurry from above. The gypsum slurry after mixing is made to flow to an outlet of the flow path while the upper surface of the gypsum slurry is always exposed to air. The gypsum slurry is fed into a pipe by free fall. The gypsum slurry is made to impinge on the far side of the pipe as viewed from the outlet and fall or to fall down the center portion of the pipe. The generation of gypsum scale is suppressed in the mixing device for mixing gypsum granules derived from wasted gypsum boards with gypsum slurry.

A manufacturing method of a honeycomb structure including: a dry mixing step of dry-mixing raw materials to form the honeycomb structure by a batch treatment, a wet mixing step of adding a liquid including at least one selected from the group consisting of water, a surfactant, a lubricant and a plasticizer to a dry mixture obtained in the dry mixing step, to perform wet mixing, a kneading step of kneading a wet mixture obtained in the wet mixing step, and a forming step of extruding a forming material prepared in the kneading step, wherein in the dry mixing step, a used forming material passed through the forming step is added as a part of the raw material, to perform dry mixing, and the kneading step includes a liquid re-adding step of further adding the liquid in a process of kneading the wet mixture.

A method of making asphalt concrete mixtures including reclaimed asphalt pavement (RAP). Variability in the fraction of binder that occurs in RAP that is able to melt and mix with virgin binder included in the concrete mixture previously made it difficult to select an appropriate amount of virgin binder. Methods described herein permit an asphalt concrete mix designer to determine the amount of virgin binder that can be combined with RAP and virgin aggregate in order to satisfy the minimum effective binder content of a job mix formula for such a concrete mix. The subject matter described herein thus permits more efficient use of RAP and permits use of RAP in higher amounts in asphalt concrete mixtures.

A foam concrete has constituents that include a cement, a sand, a coarse aggregate having a density in a range of 1400-1600 kg/m.sup.3, a water, and a foam solution. The foam solution includes a foaming agent and a foaming water. The foam concrete has a compressive strength of at least 20 MPa, a thermal conductivity of less than 0.40 W/mK and a maximum dry weight of 2000 kg/m.sup.3.

Disclosed herein is an artificial stone comprised of a first waste plastic material and a second waste plastic material, wherein the first and/or second waste plastic material is a non-recyclable or a recyclable plastic material. A method of manufacturing the artificial stone is also disclosed. The artificial stone may be used, for example, as an aggregate in a concrete mix or as a filler on a road laying base or sub-base.

A multi-leg discharge boot can include an inlet conduit and first and second outlet conduits separated by a junction portion. The inlet conduit includes an entry segment, a transition segment and a heel portion disposed therebetween. The inlet conduit can include an inlet end and a junction end. A junction portion is disposed at the junction end of the inlet conduit between first and second junction openings. The junction portion includes a substantially planar wall region that is substantially perpendicular to a main flow discharge axis.

The invention provides methods and compositions for treating wash water from concrete production with carbon dioxide. The treated wash water can be reused as mix water in fresh batches of concrete.