Pozzolanic Potentials of Fresh Cow Dung and Cow Dung Ash for Gravel Roads Construction

Abstract

Among third-world countries, gravel and earth roads form an excessively large portion of the road network when compared to paved roads. In Kenya, earth roads comprise about 47% of the road network, gravel roads 38% and surface-dressed and premixed asphalt roads 11 and 4% respectively (KENHA, 2019). It is important to note that paving roads is an expensive exercise, though pertinent, that competes for the deficient resources in the usually strained economies resulting in their easy neglect. Over the years, there has been an overreliance on cement as the primary chemical stabilizer, which has contributed to the low development of gravel and earth s due to cost reasons. In addition, the manufacture of cement is an environment-polluting activity that adds to the carbon footprint due to the gaseous pollutants released during the cement production process. This research investigated FCD and CDA as alternative stabilizers as they are readily available and eco-friendly. The effects of FCD and CDA were determined at various percentages for FCD (0%, 3%, 6%, 9%, and 12%) and CDA (0%, 3%, 6%, 9%, 12%, and 15%) both by weight was used. The index properties, compaction properties, plasticity requirements and bearing strength CBR and UCS were determined. The results show that for the mechanical stabilization with FCD, the MDD decreases with an increase in the percentage of FCD stabilizer, while OMC increased with the increase in dosages of FCD. The CBR test results showed an increase with the increase in FCD dosages where a maximum result of 54% was attained with 6% FCD replacement, further increase in FCD dosages lowered the CBR value while the UCS test results showed a maximum value was attained with 6% FCD replacement and with further increase in FCD decreased the UCS values. The chemical stabilization with CDA, the MDD showed a decrease with an increase in dosages of CDA while OMC increased with the increase in amounts of CDA. The test results for CBR showed an increase with the increase of CDA dosages while the UCS test results showed an increase with the increase of CDA dosages and attained a maximum with 6% CDA dosage and a further increase in CDA dosages showed a decrease in UCS results. Both FCD and CDA are inexpensive, readily obtainable, sustainable and eco-friendly. This will help low and middle-income countries in paving their gravel roads.