Manually Produce Clay-Based Housing Materials in Rural Area

Rural housing materials in developing countries (such as African countries) are mostly (crop) straw for roof cover, soil and tree branch for (round) wall. The houses are small with interior dark. In the case of electricity, mechanical and economic conditions are not allowed, farmers hardly know how to improve housing conditions or create economic benefits by applying manual labour, animal power, land, timber and fuel (firewood or coal). In this article, the method of manually producing baked tiles (for roof cover) and bricks (for wall) are described in detail with a set of historic pictures, which aims to inherit Chinese farmers’ wisdom and diligence (intangible cultural heritage), arouse farmers in developing countries to improve their housing conditions by self reliance, promote the rise and development of rural industry, at the same time, promote the construction of water conservancy project.


Introduction
Rural housing materials mainly contain wall and roof cover materials.The primary function is to withstand wind, rain or snow into the building (Guofeng, 2005;Tiansheng & Hong, 2010).Modern wall materials largely consist of baked bricks and mechanical moulding hollow clay bricks or concrete bricks among which the baked bricks account for 70% of wall materials (Xiaoguang, 1991).Modern roof cover materials mostly refer to baked tiles or glazed tiles.The process flow for the production of these materials mainly consists of earth cutting (with bulldozer), transferring (carry scraper), adding water (running water, hot water or steam), mixing (blender), filtrating, squeezing out (extrusion machine and conveyor belt), cutting unbaked tiles or bricks (cutting machine, plastic compression molding machine), glazing (for glazed tiles), drying, transferring into a tunnel kiln (tractor or conveyor belt) and firing (Situ, 1991;Chengcai, 1994;Xiaoxi, 2000;Zuxian, 2012).In a word, modern production method of the materials needs machine, fuel (diesel oil), electricity, etc.Farmers in developed countries have the economic ability to buy these materials.Most of them have brick & tile structured housing that is spacious and bright.
Many farmers' houses in rural area in developing countries (such as African countries) looked like haystacks.Some dry tree branches or wooden sticks were inserted into ground to form a circular enclosure and become a wall after mud put in around it.Crop straw (or cattle dung, houses of a few nomadic farmers) was covered on a conical (or planiform) framed roof.The houses were small with interior dark, the wall and roof difficult to resist extreme weather such as rainstorm or high temperature (Baixin, 2016).There was no one who did not want to change his own house into spacious and bright.However, most of them could not be affordable to buy, some even had never seen, modern construction materials.Before 1960s, there were also many houses constructed with naturally dry clay bricks for wall and crop (rice or wheat) straw for roof in rural area in China.The level of rural economy was very low.From then on, farmers forged ahead and manually produced baked tiles and bricks by self-reliance.The housing situation gradually changed.However, the traditional workshop of manually producing clay-based baked tiles and bricks gradually disappeared with the rapid development of economy.In this article, the method of manually producing baked tiles (for roof cover) and bricks (for wall) are described in detail with a set of historic pictures, which aims to inherit Chinese farmers' wisdom and diligence (intangible cultural heritage), arouse farmers in developing A piece of iron wire a with water cut and re mould rol carefully t steps (Figu (Figure 8).power and livestock power, etc.Under the premise of unavailable mechanical equipment, fuel (diesel) electricity, etc. and the condition of low economic level, manually producing clay-based tiles and bricks has applicability and feasibility.Firstly, small types of tile kiln and brick kiln are recommended to be promoted.A small amount of tiles and bricks produced for the purpose of improving the producers' own houses.Secondly, large types are tried to be built and a lot of materials produced for commercial purpose so as to improve other farmers' houses.Lastly, the great improvement of rural and urban housing construction will be realized by transition to modern production.

Produc
It is affected by climate when producing clay-based materials manually, because earth cutting and drying of unbaked tiles or bricks are handled outdoor.The optimum conditions for the production are that the temperature ≥ 5 o C, 2-4 level of wind and 60-80% of relative humidity, which mass production can be performed.It should be stopped when the lowest temperature ≤ -2 o C as the unbaked tiles or bricks will be cracked with cold.The windward side and top of stacked tiles or bricks outdoor should be covered with something when rainfall ≥ 0.5 mm.When it ≥ 5 mm drainage ditch should be dug.When the highest temperature ≥ 30 o C, relative humidity ≤ 30% and wind level ≥ 6, the unbaked tiles or bricks should be dried in the morning and evening so as to avoid direct exposure in strong sunshine.When more than 5 consecutive days of low cloud amount are ≥ 8, the drying time should be prolonged (Jinping, 2012).
Yearly total brick production in China was 600 billion, which consumed 1.3 billion m 3 of clay resource, equivalent to 46667 hectares of land destroyed each year that calculated according to 3 m of average depth of excavation (Nana, 2010).Hence, the destruction of arable land should be avoided when producing the materials manually.The production would emit harmful gases and waste water (Haiying, 1994).Therefore, the kiln should be built far away from residential area, animal farm and crop production area.
The development of agricultural production can not be separated from irrigation.There are many rivers and lakes in developing countries that can be used for irrigation.But the land that is far away from a river or lake needs irrigation canal built to get irrigation.Under the condition of limited national financial resources, construction of irrigation channel is very difficult.If guiding and administrating the construction material producers to cut earth from rivers (lakes) nearby to the area where irrigation is needed, construction of irrigation channel would be probably achieved.Assuming the earth cutting is 3 m in width and 3 m in depth, 0.144 billion meters [= 1.3/(3×3)] or 144 thousands kilometers length of canal would be finished after 600 billion bricks produced.