A hydraulic composition for the construction of pavements, and in particular for the repair of pavements, includes a hydraulic binder including a cement, 0.18% to 0.35% of a superplasticiser, where the percentage is expressed by dry weight compared to the cement, and where the superplasticiser includes a branched polymer including at least one pendant chain, with a terminal function of the phosphonate or phosphate type, and 0.25% to 2% of a setting accelerator, where the percentage is expressed by dry weight compared to the cement, where the setting accelerator includes a calcium salt, where the hydraulic composition has a Water/Cement ratio higher than 0.38 and strictly less than 0.45.

This geopolymer molding production method comprises: a mixing step (S1) for mixing a first material containing aluminum and silicon with a hydrate of an alkali stimulant containing a hydrate of an alkaline hydroxide and/or a hydrate of an alkaline silicate; a compaction step (S2) for compacting the mixture obtained in the mixing step (S1) into a compacted mixture; and a curing step (S3) for curing the compacted mixture.

Disclosed is a magnesium-based cementitious material, preparation method and application thereof. The magnesium-based cementitious material, comprising magnesite, sandstone, and water, wherein: the magnesite is provided with CaO, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, and MgO, a mass percentage of the CaO is less than 5%, a mass percentage of SiO.sub.2 is less than 5%, a mass percentage of Al.sub.2O.sub.3 is less than 5%, a mass percentage of Fe.sub.2O.sub.3 is less than 7%, a mass percentage of MgO is between 37% and 50%; the sandstone is provided with SiO.sub.2, CaO, Al.sub.2O.sub.3, and Fe.sub.2O.sub.3, a mass percentage of SiO.sub.2 is greater than 70%. The beneficial effects of this disclosure are: the cementitious material does not contain MgCl.sub.2, which avoids the reduction of the strength of the cementitious material due to the dissolution of MgCl.sub.2 in water; the magnesium-based cementitious material of this disclosure is immiscible with water and has strong water resistance.

Disclosed is a magnesium-based cementitious material, preparation method and application thereof. The magnesium-based cementitious material, comprising magnesite, sandstone, and water, wherein: the magnesite is provided with CaO, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2 O.sub.3, and MgO, a mass percentage of the CaO is less than 5%, a mass percentage of SiO.sub.2 is less than 5%, a mass percentage of Al.sub.2 O.sub.3 is less than 5%, a mass percentage of Fe.sub.2 O.sub.3 is less than 7%, a mass percentage of MgO is between 37% and 50%; the sandstone is provided with SiO.sub.2, CaO, Al.sub.2 O.sub.3, and Fe.sub.2O.sub.3, a mass percentage of SiO.sub.2 is greater than 70%. The beneficial effects of this disclosure are: the cementitious material does not contain MgCl.sub.2, which avoids the reduction of the strength of the cementitious material due to the dissolution of MgCl.sub.2 in water; the magnesium-based cementitious material of this disclosure is immiscible with water and has strong water resistance.

Drilling fluid compositions include invert emulsion fluids having an oleaginous phase, an aqueous phase, and an emulsifier composition that includes an ethoxylated alcohol compound and a polyaminated fatty acid compound. The ethoxylated alcohol compound has the formula R.sup.1—(OCH.sub.2CH.sub.2).sub.n—OH, where R.sup.1 is a hydrocarbyl group having from 8 to 22 carbon atoms and n is from 1 to 8. The ethoxylated alcohol compound has a Hydrophilic-Lipophilic Balance (HLB) of less than or equal to 6. The polyaminated fatty acid compound has the formula R.sup.2—CO—NH—CH.sub.2—CH.sub.2—N(COR.sup.2)—CH.sub.2—CH.sub.2—NH—CO—R.sup.3, where R.sup.2 is a hydrocarbyl group having from 1 to 20 carbon atoms and R.sup.3 is a hydrocarbyl group having from 1 to 10 carbon atoms or an alkylene carboxylate group having formula —R.sup.4—COOH, where R.sup.4 is a saturated or unsaturated hydrocarbylene having from 1 to 10 carbon atoms. Methods of drilling wells include operating a drill in a wellbore in the presence of drilling fluid compositions.

In one embodiment, a retarded acid system comprises an aqueous acid and a retarding surfactant. The aqueous acid may comprise from 5 wt. % to 25 wt. % of a strong acid, that is, an acid having a K.sub.a greater than or equal to 0.01. The aqueous acid may further comprise from 75 wt. % to 95 wt. % water. The retarding surfactant may have the general chemical formula R—(OC.sub.2H.sub.4).sub.X—OH where R is a hydrocarbon having from 11 to 15 carbon atoms and x is an integer from 6 to 10. The retarding surfactant may have a hydrophilic-lipophilic balance from 8 to 16.

The present disclosure discloses a method for compression casting concrete by reducing an amount of cement, including: adopting any existing concrete mix proportion designed for concrete of given strength, mixing the concrete, pouring the concrete into a mould, and compressing the concrete at a given pressure, where 28-day strength of the compacted concrete is increased; gradually reducing an amount of cement while keeping amounts of other materials unchanged, where 28-day strength of the concrete is gradually reduced until the concrete meets a design index; proportionally reducing amounts of water and cement in a last mix proportion while keeping amounts of other materials unchanged, where during compression casting of the concrete, discharge of cement paste is gradually reduced until no cement paste is discharged; and compression casting a concrete member according to a final mix proportion.

The present disclosure discloses a method for compression casting concrete to reduce the amount of cement, including: adopting any existing concrete mix proportion designed for concrete of given strength, mixing the concrete, pouring the concrete into a mould, and compressing the concrete at a given pressure, where 28-day strength of the compacted concrete is increased; gradually reducing the amount of cement while keeping the amounts of other materials unchanged, where 28-day strength of the concrete is gradually reduced until the concrete meets a design index; proportionally reducing amounts of water and cement in a last mix proportion while keeping the amounts of other materials unchanged, where during compression casting of the concrete, discharge of cement paste is gradually reduced until no cement paste is discharged; and compression casting a concrete member according to a final mix proportion.

A well bore cementing system may comprise a spacer fluid and a cement slurry. The spacer fluid may be positioned within a well bore, and the spacer fluid may comprise a first surfactant package comprising one or more surfactants. The cement slurry may be positioned within the well bore, and the cement slurry may comprise a second surfactant package comprising one or more surfactants.

A roofing tile composed of concrete material and a method for producing such a roofing tile. The concrete material contains a binder, a gravel, a light-weight aggregate, and added water. The roofing tile has at least one watercourse and a lateral interlocking joint having a covering fold and a water fold. The ratio of water to binder is less than 0.3, the light-weight aggregate is composed of a material that is hydrophobic and/or not hygroscopic, and the roofing tile has a density in the range of 1.6 g/cm.sup.3 to 1.9 g/cm.sup.3 after the hardening. The roofing tile has a thickness of 5 mm to 9 mm, preferably 7 mm to 8 mm, in the highly loaded regions, preferably in the region of the watercourse.