SK277780B6 - Self-hardening suspension - Google Patents

Abstract

Self-hardening suspension consists of 0,9 to 30,0 per cent weight of cement, 1,5 to 20,0 per cent weight of puzzolane- -siliceous additive with minimum contains of silicon dioxide 80 per cent of weight, 50 to 89,3 per cent weight of bentonite suspension and 0,2 to 2,0 per cent of weight of plasticizing and and retardation additives with advantage on base of alkaline salts of lignosulfonate and sulfonated condensators of monovalent and polyvalent aromatic alcohols.

Description

Technical field

The invention relates to a self-curing suspension used in civil engineering for building underground walls and elements.

BACKGROUND OF THE INVENTION

The self-setting suspensions hitherto used consist mainly of a cementitious binder, a clay suspension and chemical additives which regulate in particular the retardation, stability and theological properties of the suspension in the liquid state. Self-hardening suspensions are mainly used in the production of sealing underground walls, which achieve a reduction of water seepage into the foundation pit or interruption of permeable layers in the soil. As hydraulic binder, self-curing suspensions are usually cements, in particular troscortland, optionally supplemented with other components such as e.g. ash, hydraulic lime, slag and the like. A disadvantage of self-hardening suspensions with a pure cementitious binder is that they have a reduced service life in an aggressive environment or cannot be used at all. To achieve particularly higher strengths, relatively high doses of cement are required, which usually makes retardation of the solidification of the suspension more difficult and increases the abrasiveness of the environment for the mechanical parts of the excavating equipment. The use of hydraulic lime as an additional binder to cement increases strength but at the same time reduces resistance to aggressive environments. Self-curing suspensions with ash and ground slag are suitable for some types of aggressive environments. Their disadvantage is the high variability of the composition of these additives and their unavailability in the required uniform quality and in the case of fly ash also the need for high doses to achieve the desired mechanical properties. In some cases, the use of hitherto known self-curing suspensions is disadvantageous for a long curing time of at least 2 to 5 months to achieve the prescribed mechanical properties.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Self-hardening suspension according to the invention per 1 m ³ : 100 kg cement PC 400, 40 kg puzzolane silica additive, 905 1 bentonite suspension, 10 l plasticizing and retarding additives. After 1 month of curing, the hardened suspension has a simple compressive strength of 0.14 MPa and a filtration coefficient k = 5. 10'ms' ¹ .

The same parameters are achieved when using a cement self-hardening suspension with a composition per 1 m ³ :

250 kg cement PC 400, 905 l bentonite suspension, 10 l plasticizers and retardants. The comparison shows that according to the invention 150 kg of cement per 1 m ^{3 of} self-hardening suspension are saved.

Example 2

Self-hardening suspension according to the invention per 1 m ³ : 200 kg cement PC 400, 100 kg puzzolane silica additive, 885 1 bentonite suspension, 14 1 plasticizing and retarding additives. After 1 month of curing the hardened suspension has a simple compressive strength of 1.6 MPa and a filtration coefficient k = 3. 10 ' ⁰ ms' ¹ .

The same parameters are achieved when using a cement self-hardening suspension with a composition per 1 m ³ :

450 kg cement PC 400, 820 1 bentonite suspension, 20 1 plasticizing and retarding additives. The comparison shows that the process according to the invention saves 250 kg of cement per 1 in ^{3 of the} self-curing suspension.

By varying the mixing ratio of the individual material components of the self-curing suspension according to the invention, various physicochemical properties of the cured suspension can be achieved with considerable cement savings. At the same time, the underground wall filler formed according to the invention has a higher resistance to the aggressive action of groundwater.

SUMMARY OF THE INVENTION

The above-mentioned drawbacks are solved by the invention, which is based on the fact that the self-hardening suspension consists of 9.0 to 30.0% by weight. % cement, 1.5 to 20.0 wt. % of a puzzolane silica additive having a minimum silica content of 80.0% by weight, 50.0% to 89.3% by weight; % of a slurry and 0.2 to 2.0 wt. plasticizers and retardants, preferably based on alkali salts of lignosulfonates and sulfonated condensates of monovalent and polyvalent aromatic alcohols. The self-curing suspension according to the invention other suitable theological properties for the shelling of the excavated veneers and by controlling the dosing of the individual material components achieve the desired retardation time, higher hardness after hardening, shorter curing time and higher resistance to aggressive water action. The present invention saves a significant amount of energy-intensive cement.

Industrial usability

The present invention can also be used for the preparation of injectable compositions where better penetration efficacy is achieved compared to cement or cement-based injectable compositions.

Claims (1)

PATENT CLAIMS A self-curing suspension comprising 9.0 to 30.0% by weight of a puzzolane silica additive having a minimum silica content of 80% by weight, 50.0 to 89.3% by weight. % bentonite suspension and 0.2 to 2.0 wt. plasticizers and retardants, preferably based on alkali salts of lignosulfonates and sulfonated condensates of monovalent and polyvalent aromatic alcohols.