This research examines the shear strength of Sisal Fibre Reinforced Concrete (SSFRC).Sisal Fibre (SSF) addition was at 1% by weight of dry constituents, this is considered the upper limit for workable mixes in the absence of water reducing agents. Beams of various grades of concrete (20N/mm 2 to 40N/mm 2 ) were tested and they all failed in shear. Experimental results of beams were compared with modified versions of the BS 8110 formula for shear strength in concrete, to determine the best fit. The inclusion of SSF at 1% addition increased the compressive strength of the concrete mix by an average of 16.9% and the shear strength by 16%. However, the shear strengths of the SFRC are only greater than those of normal concrete of corresponding compressive strengths by 9.5%. The equation proposed may be used to estimate the shear strength of SSF reinforced concrete at this level of fibre addition.

An investigation on the effect of sisal fiber on partially replaced cement with Periwinkle Shell Ash in Concrete was carried out. Sisal fiber of 40mm length which forms 1% of the mix by weight with Periwinkle shell Ash as a partial replacement for cement was used to cast the concrete. Compressive strength test was carried out using 0%, 5%, 10%, 15%, 20%, 25% and 30% of Periwinkle Shell Ash as partial replacements of cement at different curing ages of 7, 14, 21 and 28 days. A skewed result was observed showing a significant increase in the compressive strength recorded in 21 and 28 days of curing whose peaks are at 5% replacement of PSA in the fiber-reinforced-concrete after which, there was a continuous decline in compressive strength of concrete as the percentage of PSA increased. The peak compressive strength value of 28.8 N/mm 2 was obtained at 40mm sisal fiber and at 28 days curing age. This is followed by a compressive strength value of 26.15 N/mm 2 after 21days of curing, all gotten at 5% PSA replacement. This makes 5% the optimal and apparently an exclusive PSA content for Sisal fiber-reinforced-concrete.

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Lateritic stones abound in the tropical and semi tropical areas of the world more than the igneous and other standard rocks that are used as concrete aggregates and road chippings. The increasing utilization of natural aggregate for concrete production have created negative impact on the environment. Therefore searching for alternative material which has potential to replace the use of coarse aggregate from normalrocks in concrete mix either wholly or partially is very much in need. This research presents the engineering properties of concrete containing lateritic aggregate as partial coarse aggregate replacement. The coarse aggregate was replaced by 10, 20, 30, 40 and 50% with lateritic aggregate. All the specimens were cured and compressive strength test were carried out at the age of 7, 14, 21 and 28 days respectively. The result revealed that replacement of lateritic aggregate up to 30% was able to produce lateritic concrete exhibiting the target strength which is 30 N/mm 2. However, the slump decreases as the percentage of lateritic aggregate in the mix increases, this may be due to the porosity of the lateritic aggregate due to absorption of the water in the mix. The result of the two way analysis of variance shows that both lateritic aggregate and curing age (days) has significant effects of the compressive strength of concrete.

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