EFFICACY OF BASALT AND GRANITE AS COARSE AGGREGATE IN CONCRETE MIXTURE

This present research was on the comparison of the efficacious use of basalt and granite as coarse aggregates in concrete work. In order to obtain the basis for comparison, physical and structural tests were conducted on the different materials of the concrete and the concrete samples respectively. Physical test results revealed that basalt have a specific gravity of 2.8 and 2.5, while granite have a specific gravity of 2.9 and 2.6. In density, basalt have a density of 1554.55kg/m3 while granite had a density of 1463.64kg/m3. Aggregate impact test conducted on both aggregates revealed a percentage of 11.05% for basalt and 12.63% for granite. The following structural tests were carried out: compressive strength tests, flexural and tensile strength test and the comparative results are as follows. Compressive strength for basalt 36.39N/mm2 while 37.16N/mm2 for granite. 24.81N/mm2 tensile strength for basalt while 12.57N/mm2 for granite, 31.83N/mm2 flexural strength for basalt while 27.97N/mm2 for granite. From the above results, it can be deduced that basalt has higher strength properties than granite. Therefore, more suitable for coarse aggregate in achieving higher strength with some quantity of other composition of the concrete mix when compared to granite.


INTRODUCTION
Technological advancement is one of the ways of achieving sustainable development globally. The discovery of concrete technology has brought different innovative ideas into it usage. The process of using appropriate ingredient of concrete and estimating relative quantity in other to produce the desired concrete that could stand the test of time in terms of material strength, durability and workability is termed concrete mix design Sobera and Tose (2003). Concrete which is made of cement, fine aggregates (sand) and coarse aggregates is mixed with water, harden with time, served as construction material in engineering sites. Concrete technology deals with the application of concrete at a particular proportion. However, in our contemporary society and due to civilization, many persons have deviated from thatched buildings into the constructive use of concrete materials in designing of houses, bridges, and erosion ways. Construction of buildings involves the usage of concrete in the foundations, columns, beams, slabs and other load carrying areas. Basalt are igneous rock that possess low silica content. They are dark and has a rich source of iron and magnesium. Some basalts appears glassy while others are very fine-grain. Basalt are classified on the basis of chemical and petrographic in two main categories, the tholeiitic and akali basalt. Kasim et al. (2017) evaluated the aggregates properties on the mechanical and absorption characteristics of geopolymer mortars. Three different types of aggregates consisting of river sand, crushed limestone and combined sand-limestone were used in geopolymer mortar. The findings revealed that the crushed limestone produces the highest compressive and splitting tensile strength while the combined sand-limestone shows the lowest water absorption and sorptivity capacity. Krzysztof et al. (2018) examined the effect of the morphology of coarse aggregate on the properties of selfcompacting high-performance fibre-reinforced concrete. It was reported that the morphology of the coarse aggregate had an impact on the rheological properties of the fresh concrete mixture. Mehdi et al. (2018) reported on the optimum oil palm shell content as coarse aggregate in concrete based on mechanical and durability properties. The findings revealed that oil palm shell content should not exceed 60% of the total volume of coarse aggregate. Dobiszewska et al. (2019) evaluated the effect of basalt powder addition on properties of mortar. The result revealed that the addition of the basalt powder in place of cement decreases the compressive strength. The flexural strength of the mortar was improved at specific instances. Kumar et al. (2015) investigated the use of granite waste as partial substitute to cement in concrete. The granite slurry was used as partial substitute in proportions ranging from 5% to 20% by weight of cement in concrete. The comprehensive strength, tensile strength and flextural strength were tested. The findings shows that locally available granite slurry is a good partial substitute to concrete.

MATERIALS AND METHODS
In more than two decades, lots of materials have been offered in full range for testing to suit the requirements of local, national and international civil engineering contractors, consultants as well as manufacturers, the resource industry and government agencies.

AGGREGATE CRUSHING TEST PROCEDURE
Specimen of aggregate in standard mould were subjected to a compression test under standard load conditions. The dry aggregate were made to pass through 12.5mm sieves, retained and sieved in a 10mm sieves, this was filled in a cylindrical measure of 11.5mm diameter with a 18cm height in three layers. Each layer is tempered 25 times with a standard tampering rod. The test sample was weighed and placed in the test cylinder in three layers each layer was being tampered again.

SPECIFIC GRAVITY AND WATER ABSORPTION, SIEVE ANALYSIS AND SPLIT TENSILE STRENGTH
The Aggregate impact test, Specific gravity and water absorption test, sieve analysis test and splitting analysis were performed using standard laboratory procedures as adopted by Ramakanta (2012); BS: 1881: Part 118: 1983; IS: Part 1-2 (2016) respectively.

EXPERIMENTAL METHOD
Different experimental method were adopted to test the components in order to determined physical properties of aggregate of basalt, physical properties of concrete and the density of concrete as shown in Table 1-3 and figure 5 respectively.

PHYSICAL PROPERTIES OF AGGREGATE
The physical properties of aggregate of basalt showing the specific gravity and particle size distribution is presented in Table 1 Table, basalt has shown that it has more strength than granite and is a better coarse aggregate material.  Given the result shown, basalt possess high resistance during crushing and gradual application of compressive load than granite. Hence, basalt is more preferred than granite.

WORKABILITY OF CONCRETE
The workability of the fresh concrete was determined by slump test. The slump test is a measure of the consistency of the concrete as shown in Table 3. According to the COREN method of concrete mix design, both aggregates exhibit properties of a high slump.

RESULTS AND DISCUSSION
The structural analysis properties of concrete and their responses are presented in Table 4, 5, 6, 7, 8 and 9 respectively. The compressive strength test for granite as shown on table 4 show a steady rise in the value of compressive strength as the number of days increased. The maximum strength was obtained after 28days of curing; while Fig. 2, shows a relationship between the increase in compressive strength and the number of days.

COMPRESSIVE STRENGTH FOR BASALT
The result for the compressive strength for basalt as shown in Table 5 indicate a relatively higher valued compared to that of granite after 28 days of curing. The relationship between number of days and compressive strength for basalt; while comparison between the compressive strength of granite and bassalt after 28days is as presented on Table 5. This implies that, granite have a lesser compressive strength than basalt i.e the compressive strength of basalt is relatively higher than that of granite.

SPLIT TENSILE STRENGTH TEST
The cylinder split tensile strength result for granite in Table 7, shows the result for the cylinder split tensile stremngth test for granite after 28days. The result shows the average tensile strength was 12.57N/mm 2 . Split tensile strength base on days of crushing and applied force was calculated from

= 2
Where: P is the applied load, L is the length of cylinder say 300mm and d is the diameter of cylinder say 150mm.  Where: P is the applied load, L is the length of cylinder say 300mm and d is the diameter of cylinder say 150mm.

FLEXURAL STRENGTH TEST
The beam strength of flexural after 28days is 27.97N/mm2 for granite test and the test for basalt is 31.83N/mm2 respectively. The result for the Beam flexural strength test for granite after 28days is as shown in Table 8. Table 9 shows the result for the beam flexural strength test for basalt after 28days; while Fig. 3 is a comparison of the beam flexural strength test for basalt and granite. This showed that the beam flexural strength test for granite is lesser than that of bassalt, hence, flexural strength is calculated from = 3 * * Where: P is the applied load, L is the length of sample say 300mm, b is the breath of sample say 150mm and d is the depth of sample say 150mm.

CONCLUSION
It was concluded from the test results that compressive strength increases the basalt percentage and enhances the mix strength over the conventional granite mix. This is due to the fact that basalt is denser and more durable and less water absorbing than granite. Also higher workability is obtained for more basalt aggregate content mix which reduces the cost of labour.

SOURCES OF FUNDING
None.