The fine aggregates used was river sand sieved on a 10 mm BS sieve to remove any coarse particles and the fine aggregates were ranging from 0.15 mm (150 µm) to 10 mm. The coarse aggregates used were crushed angular shaped rocks ranging from 2.36 mm to 25 mm. Table 2 shows the physical properties of both the coarse aggregates and the fine aggregates that were carried out. From these results, the conclusion was made that both aggregates satisfied the standards and therefore could be used in the production of Normal weight concrete reinforced with PALF.

Source: BS EN 109-1.

Table 3 shows the physical properties of the cement used in the study as compared to the requirement as per BS EN 197-1 Methods of physical tests for hydraulic cement (Determination of consistency of standard cement paste).

PALF were treated in 4% of Sodium Hydroxide Before chemical properties analysis and tensile strength of PALF (NaOH) solution over various duration NaOH is one of the best treatment of natural fibers, in increasing fibers roughness by chemically modifying and cleaning the fibre surface [11] [12]. Table 4 shows the chemical properties that were determined. In this way, three containers (dishes) were put in oven dry for 10 minutes to be cool. The three samples were ready for the experiment, after that, they were weighted. The samples of PALF were added on the three dishes and weighted. To calculate the moisture content it was necessary to put them in oven dry for 3 hours, and then after weighing them to see the weight after drying our 3 samples. In accordance with ASTM D854-9 the PALF were cut in equal length of 30 mm and 0.052 mm of diameter.

Wt. A = weight after 12 h of even dry 40˚C using C₂H₅OH

Wt. B = weight after 12 h of even dry 80˚C using KOH

Wt. C = weight after 12 h of even dry 80˚C using H₂SO₄

Source: BS EN 197-1.

Source: The chemical properties (i.e., proportions of cellulose, hemicellulose and lignin) of the treated four (4) fibers samples were determined based the procedure described by Direct method of cellulose, hemicelluloses and lignin [6] [13].

Water Ordinary portable water conforming to BS 1348-2 (1980) available in the laboratory with a pH of 8.1 was used in the study for mixing and curing of concrete mixes.

Determination of workability in this study was done by the slump test which was carried out in triplicate on every mix that was made and an average value obtained. Results of the slump test are presented in Figure 1 showing the average slump for each mix versus the percentage addition of PALF in the mix [14].

Considering a constant water/cement ratio of 0.54 which was used in the mix design, as seen from Figure 1, as the content of PALF was increased in the mix, there was a reduction in the workability levels as reported by a reduction in the slump values from 65 cm for normal concrete at percentage reductions of 7.69%, 15.38%, 20%, 38.46%, and 61.53% for 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF addition respectively as compared to the control. As there was a reduction in the slump with the addition of PALF in the mix, the concrete remained workable in nature. This reduction in a slump of concrete was attributed to the presence of fibers in the mix as they lump on each other reducing the slump while the mixture is still workable. Also, a reduction in the workability of fresh concrete may be caused by an adhesion within the concrete and holding the other ingredients of concrete together impeding easy flow. Therefore the mix required more compacting effort to achieve proper compaction as this would directly affect the density, strength, water absorption and hence the durability of the hardened concrete.

As portrayed in Figure 2, PALF incorporation in the concrete mix increased the water absorption of the mixes as the control had the least water absorption whereas there was a subsequent increment as the PALF were increased in the mix.

PALF added at percentages of 0.2%, 0.4%, 0.6%, 0.8% and 1% had a percentage increase in the water absorption of 9.82%, 23.21%, 31.25%, 37.50% and 47.32% respectively as compared to the control mix (0% PALF). The increment in water absorption as the PALF are increased could be as a result of the poor compaction leading to poor bonding as a result of the smooth texture of the fibers and this increased the number of pores in the concrete specimen causing it to absorb more water.

Compressive Strength of concrete with PALF [15] a reduction in compressive strength was recorded for both the 7 days, 14 days and 28 days though there was an increase in compressive strength with curing time as 28 days compressive strength values were greater than those at 7 days and 14 days curing. Percentage reductions of 3.07%, 4.21%, 6.19%, 9.14%, and 11.60% at 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively were obtained as compared to the control mix at 7 days testing, where as 1.81%, 2.47%, 3.24%, 3.87%, and 9.59% at 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively as compared to the control mix were obtained at 14 days testing, where as 1.72%, 2.37%, 3.01%, 3.82% and 5.48% percentage reductions at 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively were obtained as compared to the control mix at 28 days curing time. From these results (Figure 3) it can be seen that PALF addition had the less percentage reduction in compressive strength compared to normal strength concrete and therefore it offers better compressive strength properties as compared to other percentages of 0.8% and 1% PALF.

From these results, the conclusion can be made that the addition of PALF in normal strength concrete reduces its compressive strength. This could be attributed to the adhesion properties due to the smooth texture of the PALF in the mix which reduces the bonding properties of the concrete mix and hence more compacting energy is required to achieve the desired compressive strength of the concrete. Therefore PALF cannot be used to enhance the compressive strength properties of normal weight concrete.

The Splitting Tensile Strength at all percentages of PALF addition increased with curing time as 28 days at each percentage had a larger Splitting Tensile Strength value than those at 7 days and 14 days curing. There was a significant increment in the tensile splitting values at 1% PALF for 7 days, 14 days and 28 days curing times. There were percentage increment of 4.61%, 22.76%, 27.29%, 36.60% and 69.61% for 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively were obtained as compared to the control mix at 7 days curing time, where 3.15%, 16.07%, 23.76%, 39.45%, and 54.19%for 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively were obtained as compared to the control mix at 14 days testing, where 2.73%, 8.45%, 15.43%, 30.37%, and 51.62% for 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively were obtained as compared to the control mix at 28 days of curing time. Figure 4 shows graphically an improvement in the splitting tensile strength as the percentage of PALF were added therefore incorporating PALF as reinforced fibers on the Normal Strength Concrete can also improve first crack strength and ultimate ductility index.

It was also observed that the flexural properties were improved comparing to the control mix of normal strength concrete as the percentage of PALF increased there was an increment of flexural strength value with curing time of 28 days. Results in Table 1 show that there was an improvement in the flexural values at 1% PALF. There were percentage increment of 0.98%, 3.54%, 10.84%, 15.06% and 42.58% for 0.2%, 0.4%, 0.6%, 0.8% and 1% PALF additions respectively were obtained as compared to the control mix at 28 days curing time, but it was observed as shown in Table 5 that the compaction factor was reduced as the percentage of PALF increased.

The PALF have increased the strength of the normal strength in tensile and flexure more than in compressive, this is showing that the PALF acted more in traction than in compression within the composite.