An activating composition, in particular for concrete or industrial mortars containing hydraulic binder and/or pozzolanic material, comprises at least 40% by weight, preferably at least 50% by weight of calcium carbonate and/or magnesium carbonate particles having a d80 less than or equal to 15 .Math.m, and a d50 less than or equal to 4 .Math.m, and at least 1.5% by weight and up to 60% by weight of at least one alkaline metal salt. A binder composition is also provided, the binder composition comprising the activating composition and a component C comprising at least one hydraulic binder. The binder composition and at least one aggregate are combined to form a dry concrete or industrial mortar composition. Also provided is a process for preparing wet concrete or mortar compositions and hardened concrete or industrial mortar compositions obtained therefrom.

A hydraulic binder includes a Portland clinker having a Blaine specific surface of 4000 to 5500 cm.sup.2/g, from 2.5 to 8% of sulphate expressed by mass of SO.sub.3 relative to the mass of clinker, from 1.5 to 10% of calcium nitrite and/or calcium nitrate expressed as anhydrous mass relative to the mass of clinker and from 15 to 50% of a mineral addition including calcium carbonate by mass relative to the total mass of binder.

Mineral binder compositions with accelerated setting and/or curing including a mineral binder, at least one free-radical initiator, and at least one catalyst for the at least one free-radical initiator. The mineral binder compositions accelerated setting and hardening and are especially useful for applications at low temperatures and even below 0° C.

A shotcrete composition comprising a) a cementitious binder; b) an ettringite formation controller comprising (i) a glyoxylic acid condensate and/or a glyoxylic acid adduct; and c) an alkali-free, aluminum-based shotcrete accelerator. The invention further relates to a process comprising providing a cementitious composition comprising a) a cementitious binder, and b) an ettringite formation controller comprising (i) a glyoxylic acid condensate and/or a glyoxylic acid adduct; admixing an alkali-free, aluminum-based shotcrete accelerator to the cementitious composition to obtain a shotcrete composition; and applying the shotcrete composition onto a surface to obtain a shotcrete structure and allowing the shotcrete structure to harden. The invention also relates to a hardened shotcrete structure obtained by this process.

Mineral binder compositions with accelerated setting and/or curing including a mineral binder, at least one free-radical initiator, and at least one catalyst for the at least one free-radical initiator. The mineral binder compositions accelerated setting and hardening and are especially useful for applications at low temperatures and even below 0? C.

A method is shown for preparing cold-process bituminous coatings, in particular the preparation of wear surface dressings which method includes the steps of preparing a bituminous binder as a cationic emulsion of bitumen; preparing an aggregate comprising at least one first aggregate fraction; and forming said cold-process bituminous coating formed with at least said aggregate interpenetrated into said binder; characterized in that said step for preparing said aggregate comprises a step for coating said at least one first aggregate fraction with lime.

A shotcrete composition comprising a) a cementitious binder; b) an ettringite formation controller comprising (i) a glyoxylic acid condensate and/or a glyoxylic acid adduct; and c) an alkali-free, aluminum-based shotcrete accelerator. The invention further relates to a process comprising providing a cementitious composition comprising a) a cementitious binder, and b) an ettringite formation controller comprising (i) a glyoxylic acid condensate and/or a glyoxylic acid adduct; admixing an alkali-free, aluminum-based shotcrete accelerator to the cementitious composition to obtain a shotcrete composition; and applying the shotcrete composition onto a surface to obtain a shotcrete structure and allowing the shotcrete structure to harden. The invention also relates to a hardened shotcrete structure obtained by this process.