IntroductionPavement blocks, which are industrial products of pre-fabricated unarmed concrete, having various dimensions and special morphology, are used for pavement laying of residential projects carrying pedestrian and light vehicular traffic. Cement concrete paving blocks are precast solid products made of cement concrete. The product is made in various sizes and shapes viz. rectangular, square and round blocks of different dimensions with designs for interlocking with adjacent tiles blocks. The raw materials required for manufacture of the product are Portland cement and aggregates which are available locally in every part of the country. This paper presents a brief review of relevant researches on Pavement Blocks for influencing their properties. Johnson carried a parametric experimental study for producing paving blocks using waste glass as fine as well as coarse aggregate.Shayan and Xu reported fine glass powder for incorporation into concrete up to 30% as a pozzolanic material suppressed the Alkali Silica Reaction. Topcu and Canbaz reported the waste glass in size of 4-16 mm used as aggregate in the concrete to find reduced compressive strength of concrete. Tuncan et al showed the addition of waste glass powder (15%) into concrete increased the compressive strength of concrete as much as 13%. Kısacık also reported the compressive strength of concrete with waste glass decreased 19%. Park et al has study of 30% of waste glass with size of 0-5 mm addition into concrete decreased the compressive strength of concrete as much as 4%. Sangha et al. investigated the effect on concrete strength of green glass as an aggregate replacement. They observed that increases in the compressive strength values at the 10%, 40%, and 60% aggregate replacement by waste glass with 0- 10 mm particle size were 3%, 8% and 5% as compared with control sample without waste glass but decrease in the compressive strength value was 2% at the 20% replacement. This paper shows that the replacement of FG by FA at level of 20% by weight has significant effect on the compressive strength, flexural strength, splitting tensile strength and abrasion resistance of the paving blocks with FG compared with the control sample while the beneficial effect on these properties of CG replacement with FA by weight is little. Papayianni conducted research on paving blocks with fly ash.
Experimental InvestigationLocally available Ordinary Portland Cement (OPC) 53 confirming to IS standards was used. Fine aggregates confirming to grading zone-II of Table 4 of IS 383-1970 were used. Machine crushed black basalt aggregate, 20mm nominal size confirming to IS383-1970 was obtained from local quarry. Portable water was used in for mixing and curing this experimental work.
To start with M30 concrete mix design was carried out following IS10262-2009 & using normal ingredients including aggregates. In the next series of specimen preparation, however natural sand was replaced with 20% by waste glass as well as with 50% of stone dust. In addition to replacing natural sand, cement was also part replaced with fly ash. Fly ash addition levels were 25%, 35% and 50% by weight of cement. The experimental work included testing mechanical properties such as compressive strength, flexural strength and abrasion resistance. Almost all the specimens were water cured up to 7 days before testing.
Results and DiscussionTable 1 compares the compressive strength, flexural strength and abrasion resistance of concrete paving blocks containing waste glass, stone dust, admixture and fly ash with those cast using the plain cement concrete. As the percentage of the waste glass changes, there is variation in the strength of the paving block. The fig1 and 2 show that 20% replacement of fine aggregate by glass waste gives better compressive strength, & flexural strength respectively (Table1). The paving blocks made by replacing 25% of fly ash against cement, admixture 0.35% by weight of cement and replacement of fine aggregate by 50% of stone dust shows the best strength among the concrete pavement blocks containing other waste. The reason may be in the filling of voids by glass waste.
Figure 3: Failure of pavement blocks after flexural strength test
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- Papayianni, I. An Investigation of the Pozzolanicity and Hydraulic Reactivity of a High Line Fly ash, Magazine of concrete Research, 1987, 39 (138), pp.19-27.
- Indian standard fine aggregate confirming to IS 383:1970.
- Indian standard for particle size distribution of aggregate confirming to IS 2386: (Part I and Part III) 1963.
- Indian standard for Portland pozzolana cement (fly ash based) confirming to IS 1489 (Part I) 1991.