INTERNATIONAL CONGRESS ON RECENT ADVANCES IN SCIENCES AND TECHNOLOGY - Kuala Lumpur - Malaysia (2019-02-20)

The Study of particle size of recycled melamine waste on compressive strength of lightweight concrete.
This research is the investigating of the influence of melamine waste in lightweight concrete. Melamine formaldehyde (MF) which is the raw material that used in the production process for making melamine tableware. The waste, melamine product which is failed from quality inspection will be crushed into pellets. However, the waste of melamine, which is destroyed enhance the mechanical properties of building materials. In order to preserve the environment, the waste of melamine are ground to be tiny particle and put into lightweight concrete as the fine aggregate. In this study, the melamine formaldehyde waste is used as a fine aggregate which is the replacement of sand in cellular lightweight concrete. The ratio of cement to sand is 1:1 instead of river sand was replaced by melamine waste 25% by weight. The ratio of water to cement to aggregate is 2:4:1 respectively. Fresh concrete was controlled density at 1,300 kg/m3. The melamine fraction was separated by the Fineness Modulus (FM) according to ASTM C33 / C33M - 18 (Standard Specification for Concrete Aggregates) is FM1.25 FM1 FM0.75 and FM0.5. To study the mechanical properties of cellular lightweight concrete containing melamine waste, the experiments are separated into 2 parts. The first one is compressive strength test, 5 of each composite lightweight sample was carried out on curing age of 7, 14 and 28 days, according to ASTM C109 / C109M - 13 Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. Or [50-mm] Cube Specimens) were cast from brass mold size 50×50×50mm concrete. The second one is a water absorption property test used cast iron mold size 100×100×100mm. To cast 5 samples with 28 days of curing age, according to ASTM C642 – 97 (Standard Test Method for Density, Absorption, and Voids in Hardened Concrete). The results of the compressive strength study shown that the melamine waste mixes gave higher compressive strength compared to conventional aerated concrete. At replacement of the melamine waste is FM1.25 FM1, FM0.75 and FM0.5 gave the compressive strength at 3 days of 5.89, 7.12, 8.68 and 6.84 MPa respectively, 7 days of 5.48, 5.74, 11.31 and 8.67 MPa respectively and 28 days of 11.72, 13.84, 15.66 and 9.20 MPa respectively. The Fineness Modulus that gave the highest of compressive strength is equal to 0.75 because the size of the aggregate grading have appropriate compresses area and the bond between the concrete and the aggregate of waste. The water absorption test of lightweight concrete is increased following the decreasing of fineness modulus, but still in standard condition according to TSI 2601-2556 and ASTM C129 - 17 (Standard Specification for Nonloadbearing Concrete Masonry Units) Therefore, it cloud be concluded that melamine waste enhanced the improvement of the mechanical properties of concrete, reduced the use of sand, which is a natural resource, and promoted the utilization of waste by reuse in lightweight concrete.
Dr. Kanchala Sudtachat, Ms. Janjira Aphirakmethawong, Miss Pronpan Choedchai, Dr. Somsak Siwadamrongpong