EFFECT OF ADDING POLYVINYL ACETATE AND COCONUT SHELL ON CONCRETE

Manufacture of concrete with a mixture of coconut shell and polyvinyl acetate. The material used in this study are from the coconut shell coconut waste treatment process which is crushed to a maximum size of 20 mm, whereas polyvinyl acetate condition is milky white emulsion. This study uses laboratory experiments concrete according to standards ISO 7656: 2012 for normal concrete and developed into concrete innovation. Coconut shell as a substitute for gravel with a rate of 8% and 10%, while the addition of polyvinyl acetate in the amount of 8% and 10%. At the time of fresh concrete workmanship, testing the slump test to control the workability and homogeneity. Treatment (Curing) specimen is done by covering the paper specimens with wet cement. Compressive strength testing carried out during the 28 days of the test specimen. The results obtained on the compressive strength with the highest average percentage of materials such as concrete polyvinyl acetate 8% and 8% of coconut shell Amounting to 351 kg/cm 2 with an average density of 2199 kg/cm 3 . In each of the test object with a weight value is the quality efficiency in concrete polyvinyl acetate 8% and 8% of coconut shell.


INTRODUCTION
Concrete structure is one of the most jobs in the world. Basically, the concrete has a composition of cement, sand, aggregate, and water (Asroni, 2010). Nowadays, aggregates widely available at a price that is economical and has the quality of different, however, aggregate usage continuously in the long term, lead to the depletion of aggregate primary qualities and need a greater awareness of nature protection (Dahri and Syavir, 2013 ). In addition, the use of cement bound concrete jobs. In the industrial sector of cement, the cement manufacturing process which releases CO2 gas and energy needs will give effect to the presence of CO2 in the air (Malhotra, 1999). Carbon dioxide gas is a gas that can cause global warming.
Indonesia is a country with an area of 3,585,599 ha of coconut plantations year (2015) with a value of production of 2,920,665 tons. The industrial sector, processed coconut on coconut fruit flesh alone and partly in the form of waste. One coconut palm waste is having a tough nature, light, absorb water, textured wood, it has a quality coconut shell as aggregates.
polyvinyl acetateis an adhesive for porous materials, especially wood with adhesion (adhesivitas) high. Such materials are commercially creamy white or yellow saturated with emulsion and wet conditions. The use of inorganic or organic PVAC with concrete to make a higher density (Matsuri, 2010).

RESEARCH METHODS
Coconut shell processing as aggregates, namely, first clean the shell of coconut fibers, then wash and dry in the sun to dry. The latter process is pounding with the results of the size of 5-20 mm.

Figure 1. Coconut Shell For Aggregate
The materials used include the following, coconut shells that have been though, Polyvinyl acetate used is the brand of "Rajawali" a milky white with the conditions of the emulsion, sand originating from Lumajang, gravel with a size of 10 mm and drug concrete brand "ADDITON" type superplast.  Preparation of test specimens made as many as 20 pieces in the shape of a cube, each made with five variations of the test specimen and four specimen at each variation. The test object in the form of a cube having a side of 15 cm.
In the mixing stage, polyvinyl acetat dissolved into some of the water in the container, then soak the coconut in the container for 15 minutes to 30 minutes. At the time of stirring reserving some of the water, before the drug mixed concrete. After achieving a homogeneous fresh concrete, testing slump. In the maintenance phase of the test specimen, performed after a day old by covering the test object with cement soaked paper.
Compressive strength testing performed on the test specimen 28 days, after the drying process of care test object. Compressive strength testing conducted at the Laboratory of Civil Engineering Concrete Narotama University.
Quality relationship with a weight equal compressive strength (fc ') divided by density (kg/m 3 ). The equation to determine an efficient compressive strength against weight. The more lightweight concrete with high compressive strength value then becomes the ideal value.

RESULTS AND DISCUSSION
Stage of the examination or test performed on the laboratory aggregate Concrete Civil Engineering Narotama Surabaya. Testing fine and coarse aggregates include moisture, density, volume weight, hygiene, sieving, as the following table; At the time of setting time, polyvinyl acetat has a long drying properties to the wet, while the SP (Superplast) is accelerating the hardening. At that time experienced a hard concrete surface but the conditions are not yet fully hard inside.
Concrete treatment processes (curing) by covering the test object with wet cement and paper soaked in water. Wood textured coconut shell that can absorb water, if soaked the coconut shells become obsolete and will decrease the compressive strength of the test specimen. In testing the compressive strength, compressive strength is obtained as follows; The influence of the addition of coconut shells in concrete, can be seen in the following chart;

Figure 3. Compressive Strength Test Objects
A normal concrete compressive strength is an average of 237 kg / cm 2 . Test specimen polyvinyl acetate and coconut with a proportion of 8% and 8% have a compressive strength of 351 kg / cm 2 , the addition of 10% polyvinyl acetate and the result has decreased by 236 kg / cm 2 . While the specimen at a proportion of 10% polyvinyl acetate and 8% coconut has a compressive strength of 288 kg / cm 2 , the addition of 10% polyvinyl acetate and the result is decreased by 267kg / cm 2 . If the note is the addition of coconut decreased compressive strength In Table 4, obtained the value of quality efficiency with a specific gravity that is in material polyvinyl acetate 8% and 8% coconut shells with an average compressive strength of 351 kg / cm 2 and a density of 2199 kg / m 3 .

CONCLUSION
On the results of research and discussion that has been done can be some conclusions as follows: 1. Influence of the concrete to the addition of coconut shells are heavy concrete may be light, but the addition of coconut shell by 10% decreased the compressive strength compared to the addition of coconut shells at 8% with the compressive strength of 236 kg / cm 2 of 351 kg / cm 2 and 267 kg / cm 2 of 288 kg / cm 2 . Meanwhile, the effect of the addition of polyvinyl acetate as the added material that can bind coconut shells with concrete because the adhesion properties of polyvinyl acetate, but at the time of setting time, the influence of polyvinyl acetate which makes the concrete hardens longer than normal concrete. 2. In this study, the planned compressive strength is equal to 200 kg / cm 2 with a safety factor of 250 kg / cm 2 . On the results obtained value of the compressive strength of the average on the test object with the proportion of ingredients, among others, specimen concrete polyvinyl acetate 8%, coconut shell 8% achieved compressive strength of 351 kg / cm 2 , the test specimen concrete polyvinyl acetate 8%, coconut shell 10% achieved compressive strength of 236 kg / cm 2 , while the test specimen concrete polyvinyl acetate 10%, coconut shell 8% achieved compressive strength of 288 kg / cm 2 , and the test specimen concrete polyvinyl acetate 8%, coconut shell 10% achieve strong press at 267 kg / cm 2 . 3. The optimum mix design in terms of density and compressive strength of the concrete specimen is at 8% polyvinyl acetate, coconut shell 8% with average density of 2199 kg / m3 and a compressive strength of 351 kg / cm 2 .