A preparation method for a concrete additive for a maritime work environment includes: S1, compounding a volcanic ash material containing aluminum oxide and lime in proportion, loading a mixture into a sugar coating machine, and spraying a proper amount of alcohol, to prepare spherical particles; S2, adding the spherical particles in S1 and cement into the sugar coating machine, uniformly spraying deionized water in a rotating process, and coating surface layers of the spherical particles with a layer of cement for maintenance; and S3, placing the maintained particles in S2 into a hydrophobic emulsion, and coating the surface layers of the particles with a layer of hydrophobic emulsion, to obtain a concrete additive.

A composite cementitious feedstock comprises discrete elements. Each discrete element includes mineral rock agglutinates having irregular surface regions and cavities. Super absorbent polymer (SAP) particles and cement particles are disposed on the irregular surface regions and in the cavities. A binder coheres the agglutinates, SAP particles, and cement particles.

A composite cementitious feedstock comprises discrete elements. Each discrete element includes mineral rock agglutinates having irregular surface regions and cavities. Super absorbent polymer (SAP) particles and cement particles are disposed on the irregular surface regions and in the cavities. A binder coheres the agglutinates, SAP particles, and cement particles.

A composite cementitious feedstock includes mineral rock agglutinates, super absorbent polymer (SAP) particles, cement particles, and a binder. Each of the agglutinates has irregular surface regions and cavities originating at the irregular surface regions. At least a portion of the SAP particles and cement particles are disposed on the irregular surface regions and in the cavities. The binder coheres the agglutinates, SAP particles, and cement particles.

A preparation method for a concrete additive for a maritime work environment includes: S1, compounding a volcanic ash material containing aluminum oxide and lime in proportion, loading a mixture into a sugar coating machine, and spraying a proper amount of alcohol, to prepare spherical particles; S2, adding the spherical particles in S1 and cement into the sugar coating machine, uniformly spraying deionized water in a rotating process, and coating surface layers of the spherical particles with a layer of cement for maintenance; and S3, placing the maintained particles in S2 into a hydrophobic emulsion, and coating the surface layers of the particles with a layer of hydrophobic emulsion, to obtain a concrete additive.

Granules for a roof coating, wherein said granules comprise particles that have a coating, wherein said coating comprises at least one layer of an inorganic powder in a binder, wherein said inorganic powder has a d50 grain size of from 0.5 to 25 μm, and wherein a hydrophobizing and/or oleophobizing agent is present on said coating.

Methods for increasing the hardness of aggregate include applying a hardener to the aggregate. The hardener may react with a material of the aggregate and/or a material on a surface of the aggregate. For example, an alkali metal silicate, such as lithium polysilicate, or a colloidal silica may chemically react with calcium oxide and/or calcium hydroxide of an aggregate or on an aggregate to create cementitious material, which may at least partially fill pores in the surface of the aggregate, harden an existing microtexture of the aggregate and/or enhance the microtexture of the aggregate. These characteristics may enhance frictional characteristics, the wear characteristics and the durability of the aggregate, and of any structures formed from composite materials that include the aggregate.

Methods for increasing the hardness of aggregate include applying a hardener to the aggregate. The hardener may react with a material of the aggregate and/or a material on a surface of the aggregate. For example, an alkali metal silicate, such as lithium polysilicate, or a colloidal silica may chemically react with calcium oxide and/or calcium hydroxide of an aggregate or on an aggregate to create cementitious material, which may at least partially fill pores in the surface of the aggregate, harden an existing microtexture of the aggregate and/or enhance the microtexture of the aggregate. These characteristics may enhance frictional characteristics, the wear characteristics and the durability of the aggregate, and of any structures formed from composite materials that include the aggregate.

The invention relate to use of aqueous solution of organic ammonium carboxylate of formula (I): [NR.sup.1R.sup.2R.sup.3R.sup.4].sup.+n[R.sup.5(COO)].sup.−n, in which R.sup.1, R.sup.2, and R.sup.3 are selected from the group composing of hydrogen and methyl, R.sup.4 is a C.sub.1-C.sub.4-alkyl substituted with a hydroxyl group, R.sup.5 is hydrogen or methyl and n is 1, as a mist or drops in preventing dusting of fine material and in lowering the freezing point of said aqueous solution on the surface of said fine material or on the surface of dust particles obtained from said fine material by spraying said mist or drops onto fine material or onto dust particles obtained from said fine material to neutralize negatively charged dust particles or by changing negatively charged dust particles into positively charged dust particles, wherein said fine material is selected from the group composing of sand, crushed stone, stone powder, crushed expanded clay, or crushed expanded clay aggregate, crushed cement or concrete, cement or concrete powder, chopped organic material, minerals and metal powder.

A free-flowing powder composition includes at least one substrate having pores and an external surface between said pores, said surface functionalized with at least one accelerator for a hydraulic setting composition, said accelerator being liquid, hygroscopic, or deliquescent, and wherein after 15 minutes of immersion of free-flowing powder composition in water at 20° C. at least 80% in weight of said accelerator is solubilized, said free-flowing powder composition being immersed in an amount of water sufficient so that the saturation concentration of said accelerator cannot be reached. There is also a method for preparing said free-flowing powder composition. The use of said free-flowing powder composition as an additive for mortar or concrete composition provides an accelerating effect, an anti-ageing effect and an anti-dusting effect. A dry mortar or concrete composition includes a hydraulic binder, said free-flowing powder composition and a granulate, wet mortar or concrete composition and hardened body obtained therefrom.