EFFECT OF RICE HUSK ASH IN THE PRODUCTION OF HOLLOW SANDCRETE BLOCK

The effect of rice husk ash as a component of hollow sandcrete blocks was investigated. The objective was to reduce the present high cost of building construction. The rice hush ash used was derived from rice husk which is a bye-product of milling rice. Batching of the material was done by weight and a nominal mix proportion of 1:6 of cement and sand respectively was used. One hundred and twenty samples of hollow sandcrete blocks were produced in two different sizes 226x225x450 (mm) and 150x225x450(mm). Various proportions of rice husks ash i.e. 0%,4%,10%,20%, and 30% were used as replacement of cement in the mix. The compressive strength of the samples were determined after 28days using the universal testing machine and the average values obtained were 2.8, 2.2, 2.5, 2.0, and 1.7(N/mm2) respectively. It was concluded that rice husk ash blocks have relatively lower strength compared to blocks without rice husk ash. At 10% ash replacement however, the hollow block developed compressive value of 2.5N/mm2 which met the minimum standard required for building construction. Cost analysis showed that a saving of 5.3% per block can be achieved through the use of rice husk ash blocks. It was therefore recommended the rice block ash blocks with up to 10% replacement can be used in building construction for non-load bearing walls such as fence walls and partitions

Durability Properties of Palm Oil Fuel Ash Self Compacting Concrete

Self Compacting Concrete (SCC) is a new innovation in technology that can flow readily into place under its own self weight and fill corner areas of reinforcement structures without the need to vibrate and without segregation of its constitute. The problem of durability of concrete structures due to inadequate compaction by skilled workers has become a source of concern globally. The shortage of skilled manpower, noise and vibration of equipment on construction sites has led to the development of self compacting concrete. This paper presents an experimental study on the durability properties of Self Compacting Concrete with partial placement of Palm Oil Fuel Ash (POFA). Twelve POFA self-compacting concretes of various strength grades were designed at varying percentages of 0, 5, 10, 15, 20, 25 and 30%. The concrete with no placement of ash served as control. Conplast SP432MS was used as superplasticiser in the mix. The experiments are carried out by adopting a water-powder ratio of 0.36. Workability of the fresh concrete is determined by using tests such as: slump flow, T50, V-funnel and L-Box tests. The durability of concrete is tested by acid resistance, sulphate attack and saturated water absorption at the age of 14, 28, 56 and 90 days

Assessment of activity moduli and acidic resistance of slag-based geopolymer concrete incorporating pozzolan

The environmental impact of Portland cement production and utilization in the construction sector has led to the global call for the use of eco-friendly construction materials for the production of cleaner and sustainable products. Therefore, this study explored agro-industrial wastes, slag and corncob ash, for the production of geopolymer concrete (GPC). Corncob was dehydroxylated at 600 �C for 3 h and partially used as a replacement for slag at 0%, 20 %, 40 %, 60 %, 80 %, and 100 %. A 12 M, 14 M, and 16 M of both sodium silicate (SS) and sodium hydroxide (SH) were used as activators. The chemical moduli of each and mixed binder were quantified and evaluated based on the major reactive oxides, hence leading to the evaluation of reactivity indexes (RIs). Moreover, the RIs and mix design properties (MDPs) of concrete were used for the prediction of flexural strength while the chemical resistance of each concrete sample was investigated. Compared with the experimental results, the predictive flexural strengths based on the RIs and the MDPs yielded a high precision with R2 ranging from 88–92 % at 7–90 days, respectively. Moreover, the GPC, unlike Portland cement concrete (PCC), resisted the more acidic attack. Therefore, the use of GGBFS�CCA blended concrete would be more advantageous in a highly acidic environment than PCC. Ultimately, the models proposed by this study can be useful in the concrete mix design procedure for the flexural strength development of GPC incorporating agro-industrial provided the oxide compositions of each and mixed material were obtained

Strength Characteristics of Concrete Reinforced With Sugar Cane Bagasse Fibre

This paper examined the strength characteristics of sugar cane Bagasse fibre incorporated into concrete. The Utilization of fibre in concrete production not only solves the problem of disposing this solid waste but helps conserve natural resources. A total of 40 each for cubes, cylinders and beams were cast for this study. The cubes were of dimension 100mm×100mm×100mm, the beams were 500mm×100mm×100mm in cross-section while the cylinders were 100mm in diameter and 200mm long. Five mixes of various strength grades were prepared at varying percentages of 0, 0.5, 0.75, 1.0 and 1.25%. The concrete with no fibre served as control. Conplast SP430MS was used as superplasticiser. Water-cement ratio of 0.5 was maintained for all mixes. The design mix obtained was1:1.7:2.5. Compressive strength, flexural strength, splitting tensile strength were determined at 7, 14, 21 and 28 days of curing

Evaluation of reactivity indexes and durability properties of slag-based eopolymer concrete incorporating corn cob ash

The method of determining the quantities of geopolymer concrete (GPC) ingredients to attain the required and specifiable characteristics is complex owing to the involvement of more variables compared with Portland cement concrete (PCC) systems. Therefore, this study evaluated the hydraulic responses and chemical resistance of GPC produced with supplementary cementitious materials (SCMs), ground granulated blast furnace slag (GGBFS) and corn cob ash (CCA) at ambient curing conditions. Corn cob was dehydroxylated at 600 �C and used as a partial replacement for GGBFS at 0, 20, 40, 60, 80, and 100%. The activators used were 12, 14 and 16 M concentration (M) of both sodium silicate (SS) and sodium hydroxide (SH). The chemical compositions of individual and mixed binders were analyzed, while the chemical moduli of each and blended binder were examined and evaluated based on the significant reactive oxides, hence resulting in the evaluation of reactivity indexes (RIs). Moreover, the compressive strength was predicted based on the RIs and mix design proportions (MDPs) of the blended concrete, while the durability properties of each concrete sample were investigated. The results indicated that the oxide compositions of GGBFS and CCA influenced the compressive strength of GPC produced. Compared with the experimental results, the predictive compressive strengths based on the RIs and the MDPs yielded a high precision with 95% ‘‘R2”. Furthermore, the incorporation of both GGBFS and CCA increased the durability of GPC produced against sulfate attacks. Ultimately, the model equations developed by this study can be beneficial in the refinement of mix designs of both GPC and conventional concrete incorporating SCMs provided the oxide compositions of the elements are obtained

BUILDING A SUSTAINABLE WORLD: ECONOMY INDEX OF GEOPOLYMER CONCRETE

Geopolymer concrete offers a considerable solution not only to the environmental problem but also to the structural deterioration confronting the world. But, limited or no study is found on its cost implications. Consequently, this study evaluates the production cost and the economy index of geopolymer concrete (GPC) and compares it with the Portland cement concrete (PCC). Corncob ash (CCA) and ground granulated blast furnace slag (GGBFS) were used as source materials in the production of geopolymer concrete. Alkaline liquids were prepared to obtain 12 molar concentrations. The concentration was used to activate the source materials. Grade 30 concrete (M30) was adopted as a mix design proportion. GGBFS was replaced by CCA in varying percentages as 0%, 20%, 40%, 60%, 80%, and 100%. The research findings reveal that GPC is 27.71% lesser than the PCC in terms of production cost while the economy index of GPC is higher than the PCC for the same grade of concrete. The results infer that GPC is cheaper and more viable than the PCC. Thus, geopolymer concrete proves to be an innovative product and appears to be a feasible solution not only to the environmental and structural deteriorating problems but also to the problem of high cost of Portland cement in the construction industr

Effect of Coarse Aggregate Size and Gradation on Workability and Compressive Strength of Plain Concrete

In this study effect of coarse aggregate size and gradation on workability and compressive strength of concrete was investigated. A mix ratio of 1:2:4 with a target strength of 20/25MPa, was adopted with a water-cement ratio of 0.6. Concrete cubes were produced with uniform coarse aggregate size of 4.75, 6.7, 9.5, 13.2 and 19mm respectively, with another set of samples produced with all the coarse aggregate sizes. Slump tests were carried out for all mixes and all sets of samples were tested for compressive strength after, 7, 14 and 28 days of curing. It was observed that workability was similar for all mixes with no well-defined pattern of relationship with size of coarse aggregate used. Compressive strength was observed to increase with increase in coarse aggregate size. Authors attributed this to the less quantity of water absorbed by larger size coarse aggregate during mixing which results in lesser quantity of capillary pores after curing. Maximum compressive strength was recorded for samples with 9.5mm coarse aggregate size. These show that quality concrete can still be produced with single-sized coarse aggregate as long as the optimum size can be determined for the particular mix.&nbsp

STRENGTH PROPERTIES OF SLURRY INFILTRATED FIBROUS CONCRETE (SIFCON) PRODUCED WITH DISCRETE BAMBOO AND STEEL FIBRES

This paper examined the comparison between the mechanical properties of slurry infiltrated fibrous concrete with short steel fiber and discrete bamboo. The differences in properties of the concrete with fiber, concrete without fiber and concrete with discrete bamboo was determined. Compressive and flexural strengths of concrete and slump were also determined. A total of six mix batches of concrete containing 0% (control), 1%, 2% and 3% of steel fiber and discrete bamboo was incorporated into concrete, while 0%, 0.5%, 0.75% and 1.0% of steel fibre and discrete bamboo by volume fraction of concrete were used for flexural strength test. The bamboo stripes were sun dried, cut in sizes ranging from 50- 63mm in length and 4.4mm thick for easy mix with concrete while the steel fiber was 25mm in length and 0.4mm thick. The concrete prism used was 300mm x 100 mm x 100mm for compressive strength test and beam 350mm x 100mm x 100mm for flexural strength test. A thickness of 10mm cement slurry was infiltrated into the beam prism while the remaining 90mm thickness was filled with concrete. Plain concrete without fiber or discrete bamboo served as control. The addition of steel fibre increased the strength of concrete

Quality Management in Construction Project: Empirical Study of Covenant University Sports Complex

The acceptable level of quality in construction projects has long been a problem. Significant resources are wasted on construction projects because of inefficient or non-existent quality management procedures. Therefore, this study evaluates the quality management and the quality grading practices in the construction project with emphasis on the Covenant University Sports Complex. The quantitative research strategy and questionnaire survey were used as the main data collection instrument for soliciting information from the project participants in order to determine the best key for quality management practice. Moreover, an ultrasonic pulse velocity tester was engaged to assess and evaluate the conditions of concrete structural members. It was found out that management commitment to quality is the most key for effective quality management practices in the construction project. In addition, the ultrasonic pulse velocity (UPV) test carried out on the randomly selected structural members varied in the range 4.2km/sec to 4.6km/sec. From this, it is inferred that the quality grading and homogeneity of concrete in the tested reinforced concrete columns, beams and slabs fall in the range of “good to excellent concrete”. The findings would assist project participants in implementing an efficient quality grading and management while executing construction projects

MODELING OF HYDROGEN POTENTIAL AND COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE

The quality of alkaline liquids used in the activation of geopolymer concrete (GPC) is one of the key parameters that influences the strength of geopolymer concrete. Several studies have been conducted on the mechanical and durability properties of geopolymer concrete but the effect of variation of alkaline liquids’ quality on the strength of geopolymer concrete is still limited. Consequently, the study investigates the effect of hydrogen potential (pH) value of the alkaline liquids used in the activation of GPC mix by considering six different available products of sodium hydroxide (NaOH) pellets. Ground granulated blast furnace slag (GGBFS) and corncob ash (CCA) were utilized as source minerals, and the grade 30 (M30) concrete was adopted as mix design proportion. Sodium hydroxide pellets were prepared in 14 molar concentrations. The pH values of alkaline liquids (ALs) and the compressive strengths of the concrete were determined. The experimental findings reveal the best compressive strength with a pH value of 13.75 at 28 days curing for product A compared with pH values of 13.64, 13.61, 13.53, 13.21, and 12.89 for products B, C, D, E, and F respectively. Therefore, it is deduced that higher pH value of ALs results in higher compressive strength of GPC. The developed regression model can thus be used to predict the relationship between pH of ALs and compressive strength of GPC