PL152017B1 - Hydraulic binder - Google Patents

Description

REPUBLIC POLAND PATENT DESCRIPTION 152 017 Additional patent to patent no --- Int. Cl. ⁵ C04B 7/153 Reported: 88 03 25 (P 271470) Priority - OFFICE PATENT Application announced: 89 10 02 RP Patent description published: 1991 04 30

Creators of the invention: Anna Derdacka-Grzymek, Jan Małolepszy, Witold Brylicki, Jan Deja

The holder of the patent: Akademia Górniczo-Hutnicza im. Stanisława Staszica, Krakow, (Poland)

HYDRAULIC BINDER

The subject of the invention is a hydraulic binder that is used in particular in construction.

Hitherto known hydraulic binders are obtained on the basis of high-temperature firing processes of suitably composed mixtures, the basic type of which are binding materials based on Portland clinker. In addition to traditional Portland cements, this group also includes mixtures of clinker and other pozzolanic materials. Such a set allows to obtain a binding material with increased resistance to aggressive chemical agents. There are many practical applications of concrete where high chemical resistance combined with limited linear variations are required.

There are known cements with mineral compositions that allow for the construction of concrete structures without shrinkage or expansion. The basic ingredient of expansion cements is Portland clinker mixed with a strictly defined amount of expansion additive. The role of such an additive can be fulfilled by a specially prepared clinker containing in addition to 30a0 · SiO ^,

2CaO · SiO ^, 4CaO · Al ₂ 0 ^ · Fe ₂ 0 ^ significant amounts of calcium sulphate aluminate

3CaO · * ^Ca ^ ^o ą · Joint grinding of the clinker that expands with normal Portland clinker leads to an expansion cement. Cements containing 3-5% by weight of 3CaO. Al ₂ 0 ^ · CaSO ^ are non-shrink cements. Increase in CaSO 3Ca0.Al ₂ 0y C to about 5 - 10% by weight affords expansive cements.

Another example of an expansion cement is a mixture obtained by co-grinding 70-80% by weight of Portland clinker, 15-20% by weight of blast furnace slags, and 6-15% by weight of an expansion mixture obtained by firing a raw material consisting of gypsum, bauxite and chalk. Due to their mineral composition, expansive cements do not show high resistance to chemical corrosion. Hy152 017 binders are also known

152 017 hydraulic, non-clinker. These binders include slag-alkali binding materials produced by the activation of granular blast furnace or copper slags. These are binders characterized by high resistance to chemical corrosion and high strength. The disadvantage of mortars and concretes made of these binders is high shrinkage under the conditions of air ripening. Varying maturation conditions of these concretes and mortars lead to the formation of micro-cracks. .

The aim of the invention is to develop a hydraulic binder composition that guarantees the production of concretes and mortars with limited shrinkage or low expansion.

The binder according to the invention consists of 60-65% by weight of granular blast furnace slags, 35-40% by weight of granulated copper slags and 0-5% by weight of Portland clinker. The production of the binder according to the invention consists in grinding the components together and then activating the mixture with alkaline compounds in the process of preparing mortars and concretes. The activating compounds can be: water glass, NaOH, Na ^ SO ^ · The proposed composition of the binder mixture produces hydration products with a structure substantially different from the known slag-alkali binders.

In the known slag-alkali binders, the hydration products in the gel form constitute the essential phase of the hardened grout. This gel, drying in changing humidity conditions, causes shrinkage and microcracking of concrete.

In the binder slurries according to the invention, in addition to the gel forms, there are significant amounts of crystalline phases, mainly hydrated calcium silicates and fibrous sodium and calcium aluminosilicates. Such forms of hydration products significantly influence the linear changes of mortars and concretes.

The binder according to the invention, which is mainly a mixture of blast furnace slags and copper slags, allows obtaining crystalline products of hydration, which is not possible in the case of activation of these slags, when they do not constitute a mixture. SiO ^) ² *, while the blast furnace slag has a large amount of Ca ²⁺ ions, which in turn allows for the formation of crystalline phases such as hydrated calcium silicates and aluminum aodium-calcium silicates.

In the case of the addition of strong alkaline activators such as: NaOH, water glass, added in the amount of 2 - 15% by weight, also up to 3% by weight of Na 2 O 4, one of the first products of hydration is calcium aluminate sulphate, which causes the expansion of mortars and concretes.

Example 1 A mixture was prepared consisting of: 60% by weight of granulated copper slags, 40% by weight of granulated blast furnace slags. These components were ground together to a specific surface of 350 m ² / kg according to Blaine ^f a. From the mixture prepared in this way, a mortar was prepared with the following composition: 450 g - binder, 1350 g - standard sand, 180 g - water. Two types of activators were used for this mixture: 22.5 8 NaCH,

54.0 g of water glass with a silicate modulus of 2.8. An aqueous solution of technical water glass was used. After molding, the mortars matured in natural maturation conditions at 293 K and 95% relative humidity. The strength and linear changes of mortars were tested for up to 28 days. The test results are summarized in the tables below, of which Table 1 shows the mortar strength and Table 2 - linear changes of mortars.

Table 1

Term research Strength (MPa) NaOH water glass *. » Three days 2.1 7.9 3.5 11.9 7 days 4.3 21.4 4.9 25.4 28 days 5 * 8 yi.2 6-7 »0 * 8

152 017

Table 2

Term research Linear changes (mm / m) NaOH water glass Three days - ° ^'03 -0.03 7 days -0.08, -0.06 28 days -0.09 -0.06

Example II. A mixture was prepared consisting of: 60% by weight of granulated copper slags, 35% by weight of granulated blast furnace slags, 5% by weight of Portland clinker. The further procedure was as in Example 1, except that an activator mixture consisting of: 54.0 g of water glass with a silicate modulus equal to 28, 9.0 g of NagSO4 was used for activation. The molded mortar samples matured in natural conditions. According to PN-80 / B-04 500, linear changes of mortars were tested. The measurement results are presented in Table 3

Table 3

Examination date Linear changes mm / m Three days + 0.05 7 days + 0.18 28 days + 0.18

Claims (1)

Patent claim A hydraulic slag binder, characterized in that it consists of 60-65% ^by weight of granular blast furnace slags, 33-40% by weight of granulated copper slags and 0-5% by weight of Portland clinker.