Investigating the effectiveness of using sugarcane bagasse ash as a partial replacement of cement in construction of concrete water storage tanks.

Abstract

Bagasse is the fibrous by-product of sugarcane stalks after they are crushed to extract their juice. Sugarcane bagasse ash is a byproduct of the sugar factories found after burning sugarcane bagasse. The disposal of this material i.e. SCBA is already causing environmental problems around the sugar factories (Basika, Kigozi and Kiggundu, 2021). Due to the boost of the construction activity in the country, a huge shortage is created in most of the construction materials especially cement, resulting in steady increase of price. Cement industry also creates environmental problem by emission of carbon dioxide during manufacturing of cement and consumes lot of raw materials. This research was therefore, conducted to investigate the effectiveness of using sugarcane bagasse ash as a partial replacement of cement in construction of concrete water storage tanks. Initially, bagasse ash samples were collected from SCOUL sugar factory and its mineralogical and chemical analyses were performed with two samples of ash i.e. raw SCBA and calcined at a temperature of 900°C for 24h. After these analyses, it was observed that the calcined SCBA presented a greater tendency of material in the amorphous state, which possibly made the material the most reactive. For this reason, only the calcined SCBA was used. Also, Sucrose is the chemical name for sugar that comes from the cane and beet sugar plants. Chemically sugar consists of carbon, oxygen and hydrogen atoms and is classified as a carbohydrate. Sugar used in this study as a retarder was sucrose crystals (C12H22O11) (Kandhari, 2017). It was obtained from the local market. Sugarcane bagasse ash was sieved with 150μm sieve size. M25 grade strength of concrete was designed with nine different proportions of concrete mixes. Sugarcane bagasse ash ranging from 5% to 25% in an increment of 10% and sugar ranging from 0.2% to1.0% in an increment of 0.4% by weight of cement respectively including the control mix was prepared with a water cement ratio of 0.5. For each substitution ratio, 3 sets (a total of 60) concrete specimens were prepared for compressive strength test conducted at the age of 7 and 28 days and 20 concrete specimens for water absorption test were casted. The results of the compressive strength of concrete work have shown that up to 15% replacement of the ordinary Portland cement by bagasse ash is possible. In addition, compressive strength value of concrete with 15% SCBA replacement and 0.2% sugar was showing a higher strength improvement of about 8.9%. The water penetration depth was found to increase as the bagasse ash content increases and all the blended concretes showed a higher maximum penetration depth than the control concrete.