ANALISIS PENGGUNAAN PASIR SILIKA SEBAGAI AGREGAT HALUS UNTUK MENINGKATKATKAN KUAT TEKAN BETON MORTAR

Mortar is a building material produced from a mixture of fine aggregate, cement and water. As a filler, fine aggregate plays an important role in influencing mortar properties such as workability and strength. Mortars are used to bond construction parts, both structural such as foundations with masonry and non-structural such as walls with masonry. One important factor in mortar mixes is the fineness or coarseness of the fine aggregate, which is measured using the fine modulus (FM) value. This research aims to analyse the effect of FM variation on the compressive strength of mortar at various testing ages using silica sand as a partial replacement for fine aggregate. The tests were conducted based on SNI 7656-2012 in the laboratory of PT Fresh Beton Indonesia using the experimental method. The FM variations used were 1.87, 2.88, and 2.99, with compressive strength testing conducted at 3 days, 7 days, 14 days, and 28 days of age. The results showed that the compressive strength of the mortar increased as the testing age increased. The mortar with FM 2.99 produced the highest compressive strength of 414.08 kg/cm² at 28 days, indicating that the coarse-grained aggregate gave the best mechanical performance. FM 2.88 also gave good results, with a maximum compressive strength of 324.10 kg/cm² at 28 days. In contrast, FM 1.87 produced a lower compressive strength, with a maximum value of 306.56 kg/cm² at the same age. The use of silica sand as fine aggregate showed a trend of increasing mortar strength over time. Sands with higher FM tended to give better mechanical performance. These results indicate that sand with a near coarse FM provides optimal performance for mortar.
Keywords: Fine Modulus (FM), Mortar Compressive Strength, Silica Sand