Laboratory work №8 Theme lessons: Selection of the composition of cellular concrete

The purpose of lessons: choose the composition of cellular concrete

Equipment, tools and technical means: panoeconomicus with a capacity of 10-15 l; bowl for mixing (spherical) with the blade; moulds for cubic samples of size 7х7х7см and 10х10х10 cm; Suttard viscometer; laboratory autoclave; laboratory curing chamber, drying cabinet, press PMG; scales VLG; measuring utensils; a desiccator for storage of lime-quicklime.

The order of performance of works in the audience:

1. The students familiarize with the Standards for concrete

2. The students familiarize with the Standards for cellular concrete

3. Graduate students choose the composition of cellular concrete

4. The students calculate the composition of cellular concrete of a given composition

5. Masters prepare a blowing agent

6. Graduate students formed the control samples

7. Undergraduates produce the test specimens, determining the average density and compressive strength

8. Undergraduates making adjustments in the composition of cellular concrete

9. Undergraduates make the counting of consumption of materials for 1 m3 of finished products

Working process

This work has the purpose to teach undergraduates to determine the composition of heat-insulating cellular concrete depending on the specified properties of the applied raw materials and blowing agents.

Work is performed by teams of students for 2-3 people. Variants of tasks are shown in table 1.

Table 1 – Options jobs

№	The name cellular concrete	Curing method	View binder	View poro Converter	The type of aggregate	Density,	Strength, MPa
1	Aerated concrete	Autoclave	PTS and lime	PAK-3	Ground sand	kg/m3	12
2	Gazosilikat	Autoclave	Lime	PAK-3	Fly ash	400	12
3	Foam	Autoclave	PTS	The glue-rosin	Ground sand	450	12
4	Inosilicate	Autoclave	Lime	Kisk	Ground sand	400	12

1. Preparation and training of foam blowing agents and

To prepare the blowing agent used KK bone glue rosin, sodium hydroxide and water.

Process of preparation of foaming agent consists of the following operations: obtaining an adhesive solution, preparing an aqueous alkaline solution of rosin soap cooking, mixing the adhesive solution with rosin soap.

For glue adhesive is broken into pieces with a size of 2-3 cm, are placed into an iron pot and poured water, wherein the temperature of 15-20 ° C, in a ratio of 1: 1 (by weight). The adhesive is soaked in water time 24 h. The adhesive solution was prepared by heating the wetted adhesive at 40-50 ° C for 1.5-2 hours until it dissolves.

To prepare the rosin soap in 1 liter of water were dissolved by boiling 166 g of sodium hydroxide (solution density should be equal to 1.16). Rosin, crushed into small pieces and sieved through a sieve with holes of 5 mm, was gradually added to the boiling solution of sodium hydroxide with continuous stirring. The ratio of the rosin and a solution of sodium hydroxide should take 1: 1, the resin taken by mass (kg), and sodium hydroxide solution - in terms of volume (L). A mixture of sodium hydroxide is boiled with rosin 1.5-2 h until dissolution of rosin which is characterized by obtaining a uniform color and lack of mass lumps and grains. Evaporates by boiling water as needed fill with hot water, pre-heated to a temperature 70-80⁰C.

Mixing of the adhesive solution and the rosin soap at a ratio of 1:0.7 (by weight) of the adhesive at temperature 30⁰C and 60⁰C rosin soap. The adhesive solution was poured in small portions into a rosin soap and mixed thoroughly. The resulting mixture is called kleekanifolnym frother. Keep it should be in a glass container in a cool place at a positive temperature.

Before applying kleekanifolny foaming agent is diluted with hot water (50-60 °C) in a ratio of 1:5 (by volume). In this form it is called the working composition and can be loaded into foam mixed in foam concrete mixer.