Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets distributed throughout. Also disclosed herein are air entrainment systems and methods for manufacturing aerated low density fiber cement panels or sheets with consistent air void content and uniform air void distribution. Also disclosed herein are air entrainment technologies adapted to work in conjunction with the Hatschek process to produce aerated fiber cement articles having controlled air void content and distribution.

Fast-setting flowable fill compositions for filling ground trenches are described. The compositions set quickly but retain a low strength psi at 28 days. The compositions also reduce bleed water on the surface of the fast-setting flowable fill and therefor enable quicker application of surface repair material, e.g., pavement patches, to the trench. The compositions consist of aggregate, Portland cement, accelerant, water and sometimes air. The compositions may have a compressive strength of between 5 psi and 60 psi after 2 hours, a compressive strength of between 10 psi and 100 psi after 4 hours, a compressive strength of between 75 psi and 500 psi after 28 days, a penetration resistance of between 1.5 tsf and 75 tsf after 2 hours, a penetration resistance of between 4.5 tsf and 200 tsf after 4 hours, and a shrinkage of less than 2% as measured by ASTM C490. Also disclosed are methods of filling a trench with fast-setting flowable fill.

Fast-setting flowable fill compositions for filling ground trenches are described. The compositions set quickly but retain a low strength psi at 28 days. The compositions also reduce bleed water on the surface of the fast-setting flowable fill and therefor enable quicker application of surface repair material, e.g., pavement patches, to the trench. The compositions consist of aggregate, Portland cement, accelerant, water and sometimes air. The compositions may have a compressive strength of between 5 psi and 60 psi after 2 hours, a compressive strength of between 10 psi and 100 psi after 4 hours, a compressive strength of between 75 psi and 500 psi after 28 days, a penetration resistance of between 1.5 tsf and 75 tsf after 2 hours, a penetration resistance of between 4.5 tsf and 200 tsf after 4 hours, and a shrinkage of less than 2% as measured by ASTM C490. Also disclosed are methods of filling a trench with fast-setting flowable fill.

The present disclosure relates to the technical field of artificial cores, in particular to a preparation method of artificial sandstone and/or conglomerate core based on lithology and pore structure control. The method comprises the following steps: mixing and molding sand particles and a inorganic cementing agent in sequence, and further adding a curing agent for performing solidification to prepare an artificial sandstone and/or conglomerate core; wherein composition of the sand particles is determined according to lithology and pore structure of the artificial sandstone and/or conglomerate core. The present disclosure combines the lithology and the pore structure of the artificial sandstone and/or conglomerate core with the composition of the sand particles, particularly regulates and controls the composition of the sand particles according to the pore throat distribution pattern and the average pore throat radius, thereby performing precise control on the artificial sandstone and/or conglomerate core.

The present disclosure relates to the technical field of artificial cores, in particular to a preparation method of artificial sandstone and/or conglomerate core based on lithology and pore structure control. The method comprises the following steps: mixing and molding sand particles and a inorganic cementing agent in sequence, and further adding a curing agent for performing solidification to prepare an artificial sandstone and/or conglomerate core; wherein composition of the sand particles is determined according to lithology and pore structure of the artificial sandstone and/or conglomerate core. The present disclosure combines the lithology and the pore structure of the artificial sandstone and/or conglomerate core with the composition of the sand particles, particularly regulates and controls the composition of the sand particles according to the pore throat distribution pattern and the average pore throat radius, thereby performing precise control on the artificial sandstone and/or conglomerate core.

The geosynthetic binder dry composition includes at least: an alkalino-calcium type activator including at least lime and an alkaline salt, which can suitably react together so as to form in situ a base in the presence of water, and a silico-aluminous compound, including an amount of calcium oxide higher than or equal to 15%, by weight, as compared to the silico-aluminous compound total weight, characterized in that the binder dry composition includes, by weight, as compared to the total weight, from 45 to 95% of the silico-aluminous compound, from 2 to 25% of lime and from 3 to 30% of an alkaline salt. The material including the geosynthetic binder dry composition and water, a method for producing the geosynthetic binder dry composition, and a method for producing the material are also described.

The geosynthetic binder dry composition includes at least: an alkalino-calcium type activator including at least lime and an alkaline salt, which can suitably react together so as to form in situ a base in the presence of water, and a silico-aluminous compound, including an amount of calcium oxide higher than or equal to 15%, by weight, as compared to the silico-aluminous compound total weight, characterized in that the binder dry composition includes, by weight, as compared to the total weight, from 45 to 95% of the silico-aluminous compound, from 2 to 25% of lime and from 3 to 30% of an alkaline salt. The material including the geosynthetic binder dry composition and water, a method for producing the geosynthetic binder dry composition, and a method for producing the material are also described.

A method of producing a carbonated composite material includes: providing a carbonatable cementitious material in particulate form; mixing the carbonatable cementitious material with water to produce a mix; forming a predetermined shape with the mix, wherein the predetermined shape has an initial pore structure containing an initial pore solution having a first pH; pre-conditioning the predetermined shape to remove a predetermined amount of the water from the predetermined shape to produce a pre-conditioned shape; carbonating the pre-conditioned shape in an environment comprising carbon dioxide to produce a modified pore structure containing a modified pore solution having and a second pH, wherein the difference between the first pH and the second pH is represented by a ΔpH, and the ΔpH is 1.0 or less.

A method of producing a carbonated composite material includes: providing a carbonatable cementitious material in particulate form; mixing the carbonatable cementitious material with water to produce a mix; forming a predetermined shape with the mix, wherein the predetermined shape has an initial pore structure containing an initial pore solution having a first pH; pre-conditioning the predetermined shape to remove a predetermined amount of the water from the predetermined shape to produce a pre-conditioned shape; carbonating the pre-conditioned shape in an environment comprising carbon dioxide to produce a modified pore structure containing a modified pore solution having and a second pH, wherein the difference between the first pH and the second pH is represented by a ΔpH, and the ΔpH is 1.0 or less.

Provided is a lost circulation material that may consist essentially of an alkaline nanosilica dispersion and a sodium bicarbonate activator. Further provided are methods that may control lost circulation in a lost circulation zone in a wellbore by introducing the lost circulation material such that it contacts the lost circulation zone and forms a gelled solid in the lost circulation zone.