RU1819875C - Raw mixture for light concrete making - Google Patents

Abstract

The invention relates to the building materials industry and can be used in the manufacture of structurally insulating products and the manufacture of monolithic structures for enclosing external walls. Light concrete mixture contains, wt.%: Portland cement 4-8; fly ash 12 - 16; hydrate to 2 to 3; water 5-10; K-shell rock is known - the rest. The raw material mix for lightweight concrete is mixed with a forced action concrete mixer. The strength of concrete after TVO is 17.7-18.4 MPa, at the age of 7 days - 12.6 - 15 MPa, at the age of 28 days - 21.4 - 23.2 MPa. 2 tab.

Description

The invention relates to the building materials industry and can be used in the manufacture of structurally insulating products and the manufacture of 0 monolithic structures for enclosing external walls.

The purpose of the invention is the reduction of port, land cement while increasing the strength of concrete.

This goal is achieved in that the concrete mixture, including Portland cement, known to shell rock-fly ash and water, additionally contains hydrated lime in the following ratio, wt.%:

Portland cement 4-8 Fly ash 12-16 Hydrated lime 2-3 Water 5-10 Known for shell rock Other The essential difference of the proposed lightweight concrete mix is that the introduced components are hydrated lime Ca (OH) g. and fly ash (the content of active silica SI02 is 42 - 45%, specific surface area 2500 - 3000 cm / g) at known ratios do not exhibit chemical activity. This is explained by an insufficient quantitative ratio between them. It is also known that these components exhibit chemical activity (silicate materials), but only during autoclaving (pressure P 8 - 10 atm and temperature t 160 - 180 ° C). The introduction of hydrated lime and fly ash in the proposed ratio of the order of 1; 5, contributes to the appearance of a distinctive property unknown at other ratios, namely, the chemical interaction between the honey and, thus, the formation of calcium hydrosilicates (CaO StOa). This is especially noticeable during heat-moisture treatment (and t 80 85 ° C). Hydrated lime

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and fly ash in a 1: 5 ratio exhibit reactivity due to the necessary and sufficient amount of silica contained in fly ash and the presence of calcium oxide hydrate, and thus additional cementitious bonds are formed in the concrete.

For experimental verification of the claimed composition of light-concrete mixes, five compositions of lime forging-shell concrete with hydrated lime and a prototype were prepared.

Examples of concrete mixes are given in table 1.

Lightweight concrete mixtures were prepared by conventional mixing followed by compaction.

Strength characteristics of samples made from concrete mix, hardening under normal-moisture conditions for 7 and 28 days and after heat-moisture treatment. TVO are presented in Table 2.

From the data table. 2 it is seen that the well-known-shell-concrete of the optimal composition (Ml and IV) of the proposed mixture with a reduced consumption of Portland cement by 50% has a 35 - 48% higher compressive strength of the known composition of the prototype.

The proposed lightweight concrete mixture has increased strength due to: 1) chemical interaction of lime hydrate Ca (OH) g with active silica Zyug fly ash, which contributes to the formation of calcium hydrosilicates - a strong and waterproof substance; 2) better adhesion between limestone and limestone, which is complex in the binder and grains (creating a reinforced shell of cement-ash-limestone binder with a thickness of d 1 - 2 mm on the aggregate surface), 13) the presence of stable mechanical contact between calcium carbonates (CaCO3 ) known to shell rock and hydration products in the binder.

The combined use of the proposed components increases the strength of the known forging-shell concrete 5 (on average by 40%) compared with the prototype while reducing the consumption of Portland cement by 50%.

Claims (1)

SUMMARY OF THE INVENTION A raw material mixture for the manufacture of lightweight concrete, including Portland cement, known as shell rock, fly ash and water, which, in order to reduce cement consumption while increasing strength, it additionally contains hydrated lime in the following ratio components, wt.%: Portland Cement 4-8 Fly ash 12-16 Hydrated Lime 2-3  Water 5-10 Known for shell rock 35 Table 1 table 2