// Bangalore-specific guide · IS 456 + IS 7861

Hot Weather Concreting Guide.

April through October, Bangalore reaches 35–40°C. Concrete behaves differently. Here's what changes — and how to pour with confidence.

Today in Bangalore

34°C — Add retarder admixture

Order Temperature-Controlled Concrete Download Hot Weather Checklist

// Why hot weather matters

Three things change at once.

// NOTE · Fresh concrete

Concrete temperature rises. Slump loss accelerates. Setting time reduces (faster initial set). Risk of plastic shrinkage cracks spikes. Heat of hydration creates thermal gradients.

// NOTE · Placement

Workability window shrinks (90 min → 60 min). Curing must start faster (2 hrs vs 4 hrs). Vibration must be more aggressive. Risk of cold joints with delays.

// NOTE · Hardened concrete

Higher early strength. Lower long-term strength (15–20% reduction if not managed). Higher shrinkage. Higher permeability. Reduced durability.

// Temperature thresholds

Know your trigger points.

Ambient	Concrete temp	Action required
<30°C	<30°C	Standard mix, normal placement
30–35°C	28–32°C	Standard + retarder admixture
35–38°C	26–30°C	Chilled water, schedule early/late
>38°C	<25°C	Mandatory: Alpha Mass (temperature-controlled)

// Pre-pour planning

Before you pour.

// DO · Hot weather rules

Schedule pour for early morning (5–10 AM) or evening (5–8 PM)
Avoid 11 AM – 3 PM (peak heat)
Check weather forecast 48 hours ahead
Pre-cool aggregates with sprinkling
Wet formwork thoroughly 1–2 hours before pour
Have ice ready if ambient >35°C
Increase TM frequency (faster discharge)
Shade transit mixer queue area
Confirm water source for curing within 50 m
Have hessian + polythene + sprinklers ready
Brief workers on heat protection
Have backup labor (heat exhaustion risk)

// DON'T · Avoid at all costs

Don't pour during peak heat (11 AM – 3 PM)
Don't use hot water for mixing or curing
Don't allow concrete to sit in TM beyond 60 min in summer
Don't let formwork bake in sun before pour
Don't add water to 'freshen' concrete (5–7% strength loss per 10 L)
Don't delay curing — heat causes plastic shrinkage in hours
Don't pour mass concrete without temperature control
Don't ignore symptoms of plastic shrinkage cracks

// During pour · timed protocol

Step-by-step on the day.

Step 1
T+0
TM Arrival
- Slump test immediately
- Temperature check (target <30°C ambient + 5°C tolerance)
- Cube samples at start of pour
- Verify time from batching <60 min in hot weather
Step 2
T+5 → T+45
Placement
- Continuous discharge (don't pause)
- Aggressive vibration to prevent honeycombing
- Maintain TM intervals 8–10 minutes
- Begin fogging (light water mist) to maintain humidity around freshly placed concrete
Step 3
T+45 → T+60
Finishing
- Don't over-finish (creates weak top layer)
- Begin fogging spray immediately
- Keep top moist with sprinkler
Step 4
T+60 → T+90
Curing Start
- Cover with wet hessian + polythene
- Start water sprinkling 6–8 times daily
- Continue for minimum 14 days

// Ice & chilled water

When you need more cooling.

Chilled mixing water

Water cooled to 10–15°C at plant. Reduces concrete temperature by 4–6°C. Standard for all Alpha Mass deliveries.

Ice partial replacement

Up to 30% of mix water replaced with ice. Reduces concrete temperature by additional 5–8°C. Available at Alpha plants for premium projects.

Aggregate pre-cooling

Sprinkle aggregate stockpiles 2–3 hours before batching. Shade aggregate piles. Reduces concrete temperature by 2–3°C.

// Bangalore reality

Climate, plant-tested.

Bangalore's climate has unique characteristics for concreting. The dry summer months (March–May) combine high temperature with low humidity (15–25%) — creating high evaporation rates that accelerate plastic shrinkage cracking. Wind speeds of 20–30 km/h during pre-monsoon worsen this effect.

The pre-monsoon period (April–May) is the hardest concreting window in Bangalore. Ambient temperatures reach 38–40°C with low humidity and dust storms. This is when temperature-controlled concrete (Alpha Mass) becomes mandatory for any pour exceeding 50 cubic meters. Ice plant integration at our Ramohalli facility allows us to deliver concrete at 22–24°C even on the hottest days.

Monsoon season (June–September) brings different challenges. Concrete must be protected from rainwater dilution. Curing is easier (humidity helps), but pour timing must avoid forecast rain. Post-monsoon (October–November) is the sweet spot — moderate temperature, good humidity, predictable conditions.

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