Table 1 Physical properties of dried slurry

Specific gravity 2.40Effective aim, Dto, mm 0.12Coefficient of curvature, Cc 136Uniformity coefficient, Cu 4.58

Table 2 Chemical composition of dried slurry, %

Calcium oxide 27.37Elemental iron 16.25Quaked granite stone powder 52.80Loss on ignition 3.58

Cubes of size 703 mm x 703 mm x 70.5 mm of differentproportions of cement, sand and dried slurry were mixedwith 15% of water based on the total weight of the mix. Thecubes were cured for 7 days and their compressive strengthdetermined. Table 3 shows the compressive strength of

Table 3 7-day compressive strength of cubes of variousproportions

Mix C : S : DS• CompressiveStrength,NI mm'

CompressiveStsmelt,Nimm‘

1 : 1 : 4 4.60 1:2:7 4.001 : 1 : 5 436 1:2:8 3.321 : 1 : 6 4.24 1:3:3 5.55

1 : 1 : 7 • 3.78 1:3:4 4.851 :2: 3 5.88 1 : 3 : 5 3.701 : 2 :4 536 1:3:6 3.251 :2 : 5 5.40 I :4: 3 5.351 :2 : 6 5.30 1:4:4 4.80

C : Cement, S : Sand, DS : Dried slurry

various mixes. Economical mixes were selected from thistable for the manufactUring of building blocks based on thefollowing criteria to be satisfied. Table 4 gives the economi-cal mixes which satisfy the following conditions:

1. As per IS: 1077-1986, the minimum compressivestrenght of a brick is 3.5 N/mm2. Here, the mixes for

Utilisation of Granite Industry Waste as a Low Cost Building MaterialM R Satish Kumar, Non-memberB Kadhirvelan, Non-memberM R Sudhir Kumar, Non-member

There are many granite stone cutting and polishing industries in the North Arcot Ambedkar (NM) district ofTami I Nadu. These industries produce significant amounts of waste in the form of slurry consisting offal lime,granite powder and bon fringes as residues. Presently the dried slurry is disposed of by filling it in the lowlying areas. This leads to changes in soil fertility pollution of the groundwater and that of the surroundingenvironment. After an cioloratciry investigation of all these factors, it is found that the utilisation of slurry asbuilding blocks is one of the_,best methods of disposal.

Keywords : Granite slurry; Environmental pollution; Waste utilisation; Building blodts and bricks

INTRODUCTION

The explosion in population, acute shortage in basic resour-ces and the poor affordability of the people have necessitatedresearch in new construction materials, especially low costbuilding materials. In majority of civil engineering struc-tures, bricks are used from foundation to super structure, andhence, the bulk of construction cost is due to brick work. Itis imperative that the maximum cost economy can beachieved by reducing the cost of brick work.

In this paper an attempt is made to utilise the effluent fromgranite cutting and polishing industry for the manufacture ofbricks and hollow blocks. As a case study the effluent fromsuch an industry located near Ranipet Industrial Area isutilised.

SOURCES OF WASTE

There are many granite cutting and polishing industries inNAA district of Tamil Nadu. Granite rocks are transportedfrom different places in and around this district, which arethen cut into different sizes and shapes, and then polished tothe required degree. The cutting operation is carried outusing steel blades. To reduce the wear on blades this is doneat a pH of 8.0 to 9.0 by adding lime during .cutting process.To increase the abrasive action, iron grit is used. During envting water is added to reduce the dust formation and as acoolant This water mixes with lime powder, granite stonepowder and iron grit resulting in the formation of slurry. Inthe polishing unit, fine sand or emery-based abrasivematerial is used for polishing. During this process water isadded as a coolant This forms a slurry of granite piwder andabrasive material. The slurry from cutting operation unit andpolishing unit ultimately enters settling tanks.

RESULTS AND DISCUSSIONS

The dried slurry was analysed for the physical properties andchemical composition. The results are shown in Tables 1 and2, respectively.

M R Sails): Kumar is with Civil Engineering Department, Venom En-gingering College, Vella* 632 0141 15 Kadbh-vdan is with HindustanPetro-Chemicals Ltd, Kakinada while M R Sudhir Kumar is withNBKRIST, Vidyanagar 532 014This paper (revised) was received on October, 4, 1996. Written discussion onthe paper will be entertained Mimic 30;1997.

Vol 78, May 1997

Table 4 7-Day compressive strength of economical mixes

Mix Compressive Strength, bl/ram2

1 :1 :7 3.781:2:7 4.001:3:5_ 3.70

27

Cusat Digital Library Service http://dspace.cusat.ac.in/