Background and Justification of the project Provide sufficient background information related to this innovation/invention indicating the most recent information from relevant literature and justifying the need to undertake the project Concrete mixing can be done, either manually, with the use of such simple tools as ashovel and board or wheel-barrow, or by use of a power-driven concrete mixer. Aconcrete mixer (also commonly known as a cement mixer) is a mechanical device that homogeneously mixes cement, aggregates such as sand and gravel, and water to form concrete.In Kenya, the manual method of concrete mixing is used by small scale construction workers, who do not have the capital to acquire and use power-driven concrete mixers. Manual concrete mixing is very hard work. It should be used only for very small jobs and/or where labour is abundant and inexpensive. Moreover, with manual concrete mixing, productivity is low, such that one has to work for very long hours in order to produce a substantial amount of concrete. Further, the quality of concrete produced by manual mixing may vary, depending on the worker. In particular, the uniformity of the mix is not assured.

On the other hand, the mechanized concrete mixers that are available on the market are usually too expensive for the small operators to afford. This expense includes the purchase price as well as the cost of running the machine, usually by an electric motor or by an internal combustion engine.

The proposed innovation is intended to fill the gap between manual mixing and the expensive mechanized concrete mixers. The proposed mixer will be human powered through the use of bicycle pedals, chain sprockets and roller chains, but it will have some of the features of mechanized mixers, such as producing concrete of a more uniform mixture. Thus, the cost of fuel or electric power will be eliminated.

With the proposed concrete mixer design, it will be possible for two persons to drive it simultaneously, thus doubling the input power. In this way, the innovation will be capable of producing concrete at a substantially higher rate than manual mixing. This device will bring great advantage to the small scale construction industry, which is ever expanding, by enabling more productive, higher quality concrete mixing.