FR2503617A1 - Cellular mortar made by mixing cement and water into thick paste - and then adding foam obtd. by injecting compressed air into water contg. emulsifier - Google Patents

Abstract

A concrete mixer is employed to mix cement and water into a thick paste or slurry(a). A separate tank is used to prepare a foam (b) by adding an emulsifier to water and injecting compressed air to make a foam. The foam(b) is then added to the slurry(a) to obtain a homogeneous mixt. Foam(b) is pref. made by using a hydro-injector to add a known amt. of an emulsifier to water flow-ing along a pipe. The resulting mortar is strong, but has a low wt. and is inexpensive. It provides excellent thermal- and sound-insulation and provides a surface which is smooth or resembles ashlar. Conventional cellular concrete has a low bending strength, and uses gravel or sand which may involve large transport costs. The invention provides a strong mortar which uses neither sand nor gravel.

Description

 The present invention relates to a process for obtaining cell mortar.

 Currently we are building walls, concrete blocks or other exhibiting qualities of thermal and sound insulation in cellular concrete. These cellular concretes are obtained in a conventional manner by mixing in a concrete mixer with gravel, sand, cement and water, or by mixing gravel with cement and water, in variable proportions, to which an emulsifier is added. This foam concentrate is introduced into the mass, which is mixed in the concrete mixer, inside which is then injected with compressed air to make the whole foam.

 The elements made of aerated concrete have a high resistance to compression, but they hardly resist flexion. Indeed, the cohesion between the mortar and the gravel is poor; ruptures occur by detachment of the gravel from the mortar.

 In addition, the cost of obtaining these concretes is high, the use of sand and gravel constituting an enormous load represented in particular by the costs of purchase and transport to the place of use.

 The present invention aims to remedy these drawbacks by obtaining a cellular mortar, therefore without sand or gravel, capable of advantageously replacing the cellular concretes currently used, while ensuring better sound and thermal insulation with, in addition considerable weight gain, without affecting its resistance.

 The process for obtaining cellular mortar according to the invention consists in preparing in a concrete mixer a mortar consisting of cement and water which is mixed so as to obtain a thick slurry. Furthermore, in a tank, foam is produced by means of a generator of known type, by adding an foam concentrate in a certain amount of water, into which compressed air is injected at seven bars. The foam obtained is then projected into the concrete mixer so that it mixes with the slurry, which is kneaded until the mixture becomes homogeneous. We can then proceed with said mixture to molding of different elements, but it can also be transported by means of a worm or by any other means to the place of its use.

 A variant of the above process consists in placing on a water pipe a hydro-injector of the "Giffard" type, at the level of which the foam concentrate will be added to the water, in determined relative value, brought to a foam generator. into which air will be injected into the solution. A flow meter indicating the quantity of water required for the cell mortar can advantageously be integrated into the assembly.

This set makes it possible to obtain foam in a systematic and repetitive manner, without interruption or adjustment.

 It should be noted that compared to the known processes where the foam concentrate is added directly to the kneaded mixture in the concrete mixer, mixture in which air is then injected to obtain a cellular product, the process according to the invention in which the foam in the mortar contained in the concrete mixer, which is then kneaded to obtain a homogeneous mass, brings significant improvements with regard to the quality of thermal or sound insulation of the products produced with said mortar and in particular a superior mechanical resistance permissible their use in different fields or until now their fragility made them unsuitable.

 By way of example, a cell mortar was produced with the following composition: - slow setting cement: 10 kgs.

- water: 3.5 liters (rate increased or decreased depending on the temple
rature without, however, exceeding 9 to 10%), the whole being kneaded in a concrete mixer to obtain a thick slurry, to which 28.5 liters of foam obtained according to one of the abovementioned processes were added from - water: 2.2 liters - foam concentrate: 15 grams.

 The above values are given for information only and may vary depending on the ambient temperature, the air humidity or the value of the desired final product.

 The cellular mortar according to the invention is resistant, light, and makes it possible to obtain smooth surfaces or having the appearance of cut stone while remaining very economical. In addition, it provides better sound and thermal insulation.

Claims (2)

- CLAIMS  1. Method for obtaining cellular mortar consisting in preparing in a concrete mixer a mortar made of cement and water so as to obtain a thick slurry on the one hand, and on the other hand, to prepare in a tank of foam by addition in water, of an emulsifier, with injection of compressed air, characterized in that the foam thus produced is sprayed and mixed in the slurry constituting the mortar, which is kneaded until the mixture is homogeneous.  2. Method for obtaining cellular mortar according to 1, characterized in that the foam injected into the slurry constituting the mortar is obtained continuously by means of a hydro-injector mounted on a water pipe which will inject the foam concentrate in relative value determined in water, brought to a foam generator.