EFFECT OF MOISTURE CONTENT ON THE BEHAVIOUR OF TREATED BORASSUS IN CONCRETE

The aim of thisscientificworkis to investigate the effect of moisture content on the behaviour of borassus in concrete. At the beginning of thisstudy, characterisation tests are carried out on the materials used. These materials include Nokoué lagoonsand, rolledgravelfrom the Mono, concrete and cut-to-length rônier. Afterformulating the concrete using the DREUX - GORISSE method, the Borassus plant reinforcementsweretreated with a hydraulicwaterproofing binder (cement glue, bitumen and Flintkote Be3) and nine (09) beamswere

The aim of thisscientificworkis to investigate the effect of moisture content on the behaviour of borassus in concrete. At the beginning of thisstudy, characterisation tests are carried out on the materials used. These materials include Nokoué lagoonsand, rolledgravelfrom the Mono, concrete and cut-to-length rônier. Afterformulating the concrete using the DREUX -GORISSE method, the Borassus plant reinforcementsweretreated with a hydraulicwaterproofing binder (cement glue, bitumen and Flintkote Be3) and nine (09) beamswere made, three (03) per category of waterproofingtreatment. In addition, three (03) control beams are used as comparison materials. The analysis of all the results of the four-point bending tests led us to the conclusion that Flintkote Be3 and bitumen are very effective waterproofingproducts for the treatment of the surfaces of rônier wood beforethey are introducedinto the concrete, because the smaller the variation in the moisture content of the beams (example of PARB beam: 2.36%), the greater the resistancetheydevelop to the appliedload (example of PARB beam: 19.36 ± 1.84 kN) and consequently the lower the deformability of the beams. It thenappearsthatbitumen and Flintkote Be3 canthereforeact as a productthateliminates the dimensional variations of borassus reinforcements in concrete and provides good resistance of borassus-reinforced structures.

Introduction:-
As hygroscopicityis a property of borassus wood which causes dimensionalinstabilitywhen in contact with moisture, its association with concrete should not beleft to chance withoutperfect control of itsbehaviourwhen used as a structural element in real service situations. This leads us, in view of the studiespreviouslycarried out in the field, to focus on the behaviour of the composite in relation to the impact of the moisture content on the behaviour of borassus in concrete. Moisture exchange is a very sensitive issue, as itis one of the determiningfactorsthatcanweaken the adhesion and even the strength of the Borassus-concrete composite.
In view of the enormouspotentialthat borassus represents in construction, its association in concrete as a reinforcement in the sameway as steelis of increasinginterest to research. This raises questions about itsbehaviour in concrete. Substituting borassus for steel in concrete and ensuringthat the concrete-borassus composite willwork as a ISSN: 2320-5407 Int. J. Adv. Res. 9(03), 597-604 598 single material over time. Borassus is a hygroscopicmaterial and isthereforesubject on the one hand to dimensionalinstabilitydepending on its state and on the other hand to slippagewithin the concrete whensubjected to stress. Theseinstabilitiescan affect adhesion, whichseemsverydetrimental. L'échange d'humidité entre les deux matériaux au cours du mûrissement du composite provoque soit une diminution dimensionnelle (retrait) ce quientraine la rupture de la surface d'adhérence, soit une augmentation de dimension (absorption) qui au-delà d'une limite acceptable peut occasionner le claquage du béton.

Material:
It consistsessentially of a MIGM four-point multi-speed bendingdevice; a 10 N resolution; ahydraulicpress for compression tests.

Method for the water-repellenttreatment of roofter plant reinforcements:
Three (03) waterproofingproductswere used Flintkote Be3, whichis a cold bitumenemulsionwithoutharmfulvapours for all protection and waterproofingworks, wasapplied in twolayers of 2mm each to the walls of the rônier reinforcements and dried for 24 hours.
Oxidisedbitumenoffers good protection againstmoisture, noise, vibration and heatloss. Due to itsefficiency and usefulness in the construction field, itwasapplied hot to a thickness of 2mm on the rônier reinforcementsafter a heatingoperation. The treated reinforcement isdried for 24 hours.
Cement-glue mortarconsists of a mixture of cement, very fine sand and fixing additives. This mixture issoldready to use, either in powderform, in bags of variousquantities (from 1 to 25 kg), or in pots as a ready-to-usepaste. In our case, we used the greypowder in a 20 kg bag. To obtain the cement glue mixture, wefollowed the instructions on the packaging. Once the mixture had been obtained, weappliedit to the plant reinforcement of the rônier to a thickness of 5 mm.

H I S T O G R A M O F Q U A N T I T A T I V E R E S U L T S O F B E N D I N G T E S T S ( P A R B E A M S )
First cracking load second cracking load Arrow of the first cracking Water content

Results And Discussion:-Untreated Borassus Reinforced Beams,PAR:
Based on the results of the four-point bending test of the three (03) beams reinforced with rônier wood without water-repellenttreatment, we note that rônier wood is a living materialthatreacts to water and to variations in the humiditylevel of itsenvironment.
According to the histogram opposite, thisability of these plant reinforcements to absorb a certain amount of water depending on the humidityis a major determiningcharacteristic of the resistance of the rônier wood to stress because, according to the analysis of the histogram, the higher the water content in the extracted rônier reinforcement aftercrushing (W= 30. 21 ± 5.54 %), the greater the deflectionresultingfrom the deformation of the beams (fr = 3.41 ± 0.15 mm) and the lower the first cracking load (10.37 ± 0.86 kN ) and the breakingload (11.70 ± 0.80 kN).

H I S T O G R A M O F Q U A N T I T A T I V E R E S U L T S O F B E N D I N G T E S T S ( P A R C C B E A M S )
First cracking load second cracking load Arrow of the first cracking Water content

602
Based on the histogram of quantitative resultsfrom the bending tests of PARCC beams and compared to the data from tests on specimens of beams reinforced with rônier reinforcement withoutanypriortreatment (PAR beam), itfollowsthatcement glue is an elementthatsubstantiallyimproves the strength of the concrete-rônier reinforcement composite material.
This isexplained by the factthat the first cracking load (11.63 ± 1.30 kN) and the breakingload (15.88 ± 0.45 kN) of the PARCC beams are higherthanthose of the PAR beams by 1.26 kN and 4.18 kN respectively. With a water content of 23.56 ± 0.82% after the drying process in an oven at a temperature of 105°C, the cementitiousadhesivedid not revealitself as a productthatwould waterproof the walls of the rônier reinforcements in contact with the concrete for 28 days.

Reinforced Beams of Borassus treated with Flintkote Be3, PARF:
After the extraction of the rônier frames having undergone flintkote water-repellent treatment we notice -according to the histogram below -a relatively small increase in water content of 3.21 % (12 % ⇒15.21 %) with a rather high breaking load (19.05 ± 0.73 kN) compared to the first two treatments and a rather smaller first cracking deflection.
Therefore, we conclude that flintkote is not only a waterproofing product but also a product that improves the resistance of the composite material to bending stresse

Reinforced Beams of Borassus treated with heatedBitumenbread,PARB
Wood issaid to be "green" or "wet" whenitsmoisture content isabove 19% and "dry" whenitisbelow. According to the analysis of the histogram of the PARB beams, the bitumenplayeditsrole in waterproofing the walls of the rônier

H I S T O G R A M O F Q U A N T I T A T I V E R E S U L T S O F B E N D I N G T E S T S ( P A R F B E A M S )
First cracking load second cracking load 603 plant reinforcements in contact with the concrete by keeping the wood in its dry state (14.63% moisture content at 28 days). As the breakingload (19.36 ± 1.84 kN) wasmuchhigherthanthat of the untreatedreinforcements (11.70 ± 0.80 kN), we note in this respect that the PARB beamsdeveloped a high breakingstrengththanks to theirbetter mechanical properties.

Conclusion:-
At the end of ourstudy on "the effect of moisture content on the behaviour of borassus in concrete", itwasgenerallyfoundthattreatment with waterproofingproductssuch as Flintkote Be3 or Bitumenallows the improvement of resistancethroughdimensional stabilisation via the stabilisation of the moisture content of the borassus plant reinforcements and its optimisation through the application of cement glue. Indeed, itisalsonecessary to specifythatthisworkcarried out istakenintoaccount in the study of a prestressed borassus reinforced beam.